wip

- restore if IPv4 set all policies fails
- fix deadlock when using iptables custom rules
- fix setting ipv6 rules when running runMixedIptablesInstruction

.devcontainer/Dockerfile

@@ -1,2 +1,2 @@
-FROM qmcgaw/godevcontainer:v0.20-alpine
-RUN apk add wireguard-tools htop openssl
+FROM ghcr.io/qdm12/godevcontainer:v0.21-alpine
+RUN apk add wireguard-tools htop openssl tcpdump iptables nftables

.devcontainer/README.md

@@ -19,16 +19,16 @@ It works on Linux, Windows (WSL2) and OSX.
     mkdir -p ~/.ssh
     ```
 
-1. **For Docker on OSX**: ensure the project directory and your home directory `~` are accessible by Docker.
+1. **For OSX hosts**: ensure the project directory and your home directory `~` are accessible by Docker.
 1. Open the command palette in Visual Studio Code (CTRL+SHIFT+P).
-1. Select `Dev Containers: Open Folder in Container...` and choose the project directory.
+1. Select `Dev-Containers: Open Folder in Container...` and choose the project directory.
 
 ## Customization
 
 For any customization to take effect, you should "rebuild and reopen":
 
 1. Open the command palette in Visual Studio Code (CTRL+SHIFT+P)
-2. Select `Dev Containers: Rebuild Container`
+2. Select `Dev-Containers: Rebuild Container`
 
 Changes you can make are notably:
 

.devcontainer/devcontainer.json

@@ -82,6 +82,9 @@
                 "gopls": {
                     "usePlaceholders": false,
                     "staticcheck": true,
+                    "ui.diagnostic.analyses": {
+                        "ST1000": false
+                    },
                     "formatting.gofumpt": true,
                 },
                 "go.lintTool": "golangci-lint",

.github/ISSUE_TEMPLATE/bug.yml

@@ -67,7 +67,6 @@ body:
         - VPNSecure.me
         - VPNUnlimited
         - VyprVPN
-        - WeVPN
         - Windscribe
     validations:
       required: true

.github/ISSUE_TEMPLATE/provider.md

@@ -6,12 +6,35 @@ labels: ":bulb: New provider"
 
 ---
 
-One of the following is required:
+Important notes:
 
-- Publicly accessible URL to a zip file containing the Openvpn configuration files
-- Publicly accessible URL to a structured (JSON etc.) list of servers **and attach** an example Openvpn configuration file for both TCP and UDP
+- There is no need to support both OpenVPN and Wireguard for a provider, but it's better to support both if possible
+- We do **not** implement authentication to access servers information behind a login. This is way too time consuming unfortunately
+- If it's not possible to support a provider natively, you can still use the [the custom provider](https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/custom.md)
+
+## For Wireguard
+
+Wireguard can be natively supported ONLY if:
+
+- the `PrivateKey` field value is the same across all servers for one user account
+- the `Address` field value is:
+  - can be found in a structured (JSON etc.) list of servers publicly available; OR
+  - the same across all servers for one user account
+- the `PublicKey` field value is:
+  - can be found in a structured (JSON etc.) list of servers publicly available; OR
+  - the same across all servers for one user account
+- the `Endpoint` field value:
+  - can be found in a structured (JSON etc.) list of servers publicly available
+  - can be determined using a pattern, for example using country codes in hostnames
+
+If any of these conditions are not met, Wireguard cannot be natively supported or there is no advantage compared to using a custom Wireguard configuration file.
+
+If **all** of these conditions are met, please provide an answer for each of them.
+
+## For OpenVPN
+
+OpenVPN can be natively supported ONLY if one of the following can be provided, by preference in this order:
+
+- Publicly accessible URL to a structured (JSON etc.) list of servers **and attach** an example Openvpn configuration file for both TCP and UDP; OR
+- Publicly accessible URL to a zip file containing the Openvpn configuration files; OR
 - Publicly accessible URL to the list of servers **and attach** an example Openvpn configuration file for both TCP and UDP
-
-If the list of servers requires to login **or** is hidden behind an interactive configurator,
-you can only use a custom Openvpn configuration file.
-[The Wiki's OpenVPN configuration file page](https://github.com/qdm12/gluetun-wiki/blob/main/setup/openvpn-configuration-file.md) describes how to do so.

.github/labels.yml

@@ -86,8 +86,6 @@
   color: "cfe8d4"
 - name: "☁️ Vyprvpn"
   color: "cfe8d4"
-- name: "☁️ WeVPN"
-  color: "cfe8d4"
 - name: "☁️ Windscribe"
   color: "cfe8d4"
 

.github/pull_request_template.md

@@ -0,0 +1,12 @@
+# Description
+
+<!-- Please describe the reason for the changes being proposed. -->
+
+# Issue
+
+<!-- Please link to the issue(s) this change relates to. -->
+
+# Assertions
+
+* [ ] I am aware that we do not accept manual changes to the servers.json file <!-- If this is your goal, please consult https://github.com/qdm12/gluetun-wiki/blob/main/setup/servers.md#update-using-the-command-line -->
+* [ ] I am aware that any changes to settings should be reflected in the [wiki](https://github.com/qdm12/gluetun-wiki/)

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
     env:
       DOCKER_BUILDKIT: "1"
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: reviewdog/action-misspell@v1
         with:
@@ -45,6 +45,7 @@ jobs:
           level: error
           exclude: |
             ./internal/storage/servers.json
+            ./golangci.yml
             *.md
 
       - name: Linting
@@ -59,13 +60,46 @@ jobs:
       - name: Run tests in test container
         run: |
           touch coverage.txt
-          docker run --rm --device /dev/net/tun \
+          docker run --rm --cap-add=NET_ADMIN --device /dev/net/tun \
           -v "$(pwd)/coverage.txt:/tmp/gobuild/coverage.txt" \
           test-container
 
+      - name: Verify dev cross platform compatibility
+        run: docker build --target xcompile .
+
       - name: Build final image
         run: docker build -t final-image .
 
+  verify-private:
+    if: |
+      github.repository == 'qdm12/gluetun' &&
+      (
+        github.event_name == 'push' ||
+        github.event_name == 'release' ||
+        (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository && github.actor != 'dependabot[bot]')
+      )
+    needs: [verify]
+    runs-on: ubuntu-latest
+    environment: secrets
+    steps:
+      - uses: actions/checkout@v6
+
+      - run: docker build -t qmcgaw/gluetun .
+
+      - name: Setup Go for CI utility
+        uses: actions/setup-go@v6
+        with:
+          go-version-file: ci/go.mod
+
+      - name: Build utility
+        run: go build -C ./ci -o runner ./cmd/main.go
+
+      - name: Run Gluetun container with Mullvad configuration
+        run: echo -e "${{ secrets.MULLVAD_WIREGUARD_PRIVATE_KEY }}\n${{ secrets.MULLVAD_WIREGUARD_ADDRESS }}" | ./ci/runner mullvad
+
+      - name: Run Gluetun container with ProtonVPN configuration
+        run: echo -e "${{ secrets.PROTONVPN_WIREGUARD_PRIVATE_KEY }}" | ./ci/runner protonvpn
+
   codeql:
     runs-on: ubuntu-latest
     permissions:
@@ -73,15 +107,15 @@ jobs:
       contents: read
       security-events: write
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/checkout@v6
+      - uses: actions/setup-go@v6
         with:
-          go-version: "^1.23"
-      - uses: github/codeql-action/init@v3
+          go-version-file: go.mod
+      - uses: github/codeql-action/init@v4
         with:
           languages: go
-      - uses: github/codeql-action/autobuild@v3
-      - uses: github/codeql-action/analyze@v3
+      - uses: github/codeql-action/autobuild@v4
+      - uses: github/codeql-action/analyze@v4
 
   publish:
     if: |
@@ -91,14 +125,14 @@ jobs:
         github.event_name == 'release' ||
         (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository && github.actor != 'dependabot[bot]')
       )
-    needs: [verify, codeql]
+    needs: [verify, verify-private, codeql]
     permissions:
       actions: read
       contents: read
       packages: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       # extract metadata (tags, labels) for Docker
       # https://github.com/docker/metadata-action

.github/workflows/closed-issue.yml

@@ -9,7 +9,7 @@ jobs:
       issues: write
     runs-on: ubuntu-latest
     steps:
-      - uses: peter-evans/create-or-update-comment@v4
+      - uses: peter-evans/create-or-update-comment@v5
         with:
           token: ${{ github.token }}
           issue-number: ${{ github.event.issue.number }}

.github/workflows/configs/mlc-config.json

@@ -8,6 +8,7 @@
   "retryOn429": false,
   "fallbackRetryDelay": "30s",
   "aliveStatusCodes": [
-    200
+    200,
+    429
   ]
 }

.github/workflows/labels.yml

@@ -11,7 +11,7 @@ jobs:
       issues: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: crazy-max/ghaction-github-labeler@v5
         with:
           yaml-file: .github/labels.yml

.github/workflows/markdown.yml

@@ -18,12 +18,12 @@ jobs:
       actions: read
       contents: read
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: DavidAnson/markdownlint-cli2-action@v18
+      - uses: DavidAnson/markdownlint-cli2-action@v21
         with:
           globs: "**.md"
-          config: .markdownlint.json
+          config: .markdownlint-cli2.jsonc
 
       - uses: reviewdog/action-misspell@v1
         with:

.github/workflows/opened-issue.yml

@@ -9,7 +9,7 @@ jobs:
       issues: write
     runs-on: ubuntu-latest
     steps:
-      - uses: peter-evans/create-or-update-comment@v4
+      - uses: peter-evans/create-or-update-comment@v5
         with:
           token: ${{ github.token }}
           issue-number: ${{ github.event.issue.number }}

.golangci.yml

@@ -1,27 +1,74 @@
-linters-settings:
-  misspell:
-    locale: US
+version: "2"
 
-issues:
-  exclude-rules:
-    - path: _test\.go
-      linters:
-        - dupl
-        - err113
-        - containedctx
-        - maintidx
-    - path: "internal\\/server\\/.+\\.go"
-      linters:
-        - dupl
-    - text: "returns interface \\(github\\.com\\/vishvananda\\/netlink\\.Link\\)"
-      linters:
-        - ireturn
-    - path: "internal\\/openvpn\\/pkcs8\\/descbc\\.go"
-      text: "newCipherDESCBCBlock returns interface \\(github\\.com\\/youmark\\/pkcs8\\.Cipher\\)"
-      linters:
-        - ireturn
+formatters:
+  enable:
+    - gci
+    - gofumpt
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
 
 linters:
+  settings:
+    misspell:
+      locale: US
+    goconst:
+      ignore-string-values:
+        # commonly used settings strings
+        - "^disabled$"
+        # Firewall and routing strings
+        - "^(ACCEPT|DROP)$"
+        - "^--append$"
+        - "^--delete$"
+        - "^all$"
+        - "^(tcp|udp)$"
+        # Server route strings
+        - "^/status$"
+
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    rules:
+      - linters:
+          - containedctx
+          - dupl
+          - err113
+          - maintidx
+        path: _test\.go
+      - linters:
+          - dupl
+        path: internal\/server\/.+\.go
+      - linters:
+          - ireturn
+        text: returns interface \(golang\.org\/x\/sys\/unix\.Sockaddr\)
+      - linters:
+          - ireturn
+        path: internal\/openvpn\/pkcs8\/descbc\.go
+        text: newCipherDESCBCBlock returns interface \(github\.com\/youmark\/pkcs8\.Cipher\)
+      - linters:
+          - revive
+        path: internal\/provider\/(common|utils)\/.+\.go
+        text: "var-naming: avoid (bad|meaningless) package names"
+      - linters:
+          - lll
+        source: "^// https://.+$"
+      - linters:
+          - err113
+          - mnd
+        path: ci\/.+\.go
+
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
   enable:
     # - cyclop
     # - errorlint
@@ -42,7 +89,6 @@ linters:
     - exhaustive
     - fatcontext
     - forcetypeassert
-    - gci
     - gocheckcompilerdirectives
     - gochecknoglobals
     - gochecknoinits
@@ -51,9 +97,7 @@ linters:
     - gocritic
     - gocyclo
     - godot
-    - gofumpt
     - goheader
-    - goimports
     - gomoddirectives
     - goprintffuncname
     - gosec
@@ -86,7 +130,6 @@ linters:
     - rowserrcheck
     - sqlclosecheck
     - tagalign
-    - tenv
     - thelper
     - tparallel
     - unconvert

.markdownlint-cli2.jsonc

@@ -0,0 +1,9 @@
+{
+  "config": {
+    "default": true,
+    "MD013": false,
+  },
+  "ignores": [
+    ".github/pull_request_template.md"
+  ]
+}

.markdownlint.json

@@ -1,3 +0,0 @@
-{
-  "MD013": false
-}

.vscode/launch.json

@@ -1,35 +0,0 @@
-{
-    "version": "0.2.0",
-    "configurations": [
-        {
-            "name": "Update a VPN provider servers data",
-            "type": "go",
-            "request": "launch",
-            "cwd": "${workspaceFolder}",
-            "program": "cmd/gluetun/main.go",
-            "args": [
-                "update",
-                "${input:updateMode}",
-                "-providers",
-                "${input:provider}"
-            ],
-        }
-    ],
-    "inputs": [
-        {
-            "id": "provider",
-            "type": "promptString",
-            "description": "Please enter a provider (or comma separated list of providers)",
-        },
-        {
-            "id": "updateMode",
-            "type": "pickString",
-            "description": "Update mode to use",
-            "options": [
-                "-maintainer",
-                "-enduser"
-            ],
-            "default": "-maintainer"
-        },
-    ]
-}

.vscode/tasks.json

@@ -0,0 +1,51 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Update a VPN provider servers data",
+            "type": "shell",
+            "command": "go",
+            "args": [
+                "run",
+                "./cmd/gluetun/main.go",
+                "update",
+                "${input:updateMode}",
+                "-providers",
+                "${input:provider}"
+            ],
+        },
+        {
+            "label": "Add a Gluetun Github Git remote",
+            "type": "shell",
+            "command": "git",
+            "args": [
+                "remote",
+                "add",
+                "${input:githubRemoteUsername}",
+                "git@github.com:${input:githubRemoteUsername}/gluetun.git"
+            ],
+        }
+    ],
+    "inputs": [
+        {
+            "id": "provider",
+            "type": "promptString",
+            "description": "Please enter a provider (or comma separated list of providers)",
+        },
+        {
+            "id": "updateMode",
+            "type": "pickString",
+            "description": "Update mode to use",
+            "options": [
+                "-maintainer",
+                "-enduser"
+            ],
+            "default": "-maintainer"
+        },
+        {
+            "id": "githubRemoteUsername",
+            "type": "promptString",
+            "description": "Please enter a Github username",
+        },
+    ]
+}

Dockerfile

@@ -1,19 +1,19 @@
-ARG ALPINE_VERSION=3.20
-ARG GO_ALPINE_VERSION=3.20
-ARG GO_VERSION=1.23
-ARG XCPUTRANSLATE_VERSION=v0.6.0
-ARG GOLANGCI_LINT_VERSION=v1.61.0
+ARG ALPINE_VERSION=3.22
+ARG GO_ALPINE_VERSION=3.22
+ARG GO_VERSION=1.25
+ARG XCPUTRANSLATE_VERSION=v0.9.0
+ARG GOLANGCI_LINT_VERSION=v2.4.0
 ARG MOCKGEN_VERSION=v1.6.0
 ARG BUILDPLATFORM=linux/amd64
 
-FROM --platform=${BUILDPLATFORM} qmcgaw/xcputranslate:${XCPUTRANSLATE_VERSION} AS xcputranslate
-FROM --platform=${BUILDPLATFORM} qmcgaw/binpot:golangci-lint-${GOLANGCI_LINT_VERSION} AS golangci-lint
-FROM --platform=${BUILDPLATFORM} qmcgaw/binpot:mockgen-${MOCKGEN_VERSION} AS mockgen
+FROM --platform=${BUILDPLATFORM} ghcr.io/qdm12/xcputranslate:${XCPUTRANSLATE_VERSION} AS xcputranslate
+FROM --platform=${BUILDPLATFORM} ghcr.io/qdm12/binpot:golangci-lint-${GOLANGCI_LINT_VERSION} AS golangci-lint
+FROM --platform=${BUILDPLATFORM} ghcr.io/qdm12/binpot:mockgen-${MOCKGEN_VERSION} AS mockgen
 
 FROM --platform=${BUILDPLATFORM} golang:${GO_VERSION}-alpine${GO_ALPINE_VERSION} AS base
 COPY --from=xcputranslate /xcputranslate /usr/local/bin/xcputranslate
 # Note: findutils needed to have xargs support `-d` flag for mocks stage.
-RUN apk --update add git g++ findutils
+RUN apk --update add git g++ findutils iptables
 ENV CGO_ENABLED=0
 COPY --from=golangci-lint /bin /go/bin/golangci-lint
 COPY --from=mockgen /bin /go/bin/mockgen
@@ -32,7 +32,7 @@ ENTRYPOINT go test -race -coverpkg=./... -coverprofile=coverage.txt -covermode=a
 
 FROM --platform=${BUILDPLATFORM} base AS lint
 COPY .golangci.yml ./
-RUN golangci-lint run --timeout=10m
+RUN golangci-lint run
 
 FROM --platform=${BUILDPLATFORM} base AS mocks
 RUN git init && \
@@ -46,6 +46,10 @@ RUN git init && \
     git diff --exit-code && \
     rm -rf .git/
 
+FROM --platform=${BUILDPLATFORM} base AS xcompile
+RUN GOOS=darwin go build -o /dev/null ./...
+RUN GOOS=windows go build -o /dev/null ./...
+
 FROM --platform=${BUILDPLATFORM} base AS build
 ARG TARGETPLATFORM
 ARG VERSION=unknown
@@ -106,8 +110,11 @@ ENV VPN_SERVICE_PROVIDER=pia \
     WIREGUARD_PERSISTENT_KEEPALIVE_INTERVAL=0 \
     WIREGUARD_ADDRESSES= \
     WIREGUARD_ADDRESSES_SECRETFILE=/run/secrets/wireguard_addresses \
-    WIREGUARD_MTU=1320 \
+    WIREGUARD_MTU= \
     WIREGUARD_IMPLEMENTATION=auto \
+    # PMTUD
+    PMTUD_ICMP_ADDRESSES=1.1.1.1,8.8.8.8 \
+    PMTUD_TCP_ADDRESSES=1.1.1.1:443,8.8.8.8:443,1.1.1.1:53,8.8.8.8:53,[2606:4700:4700::1111]:53,[2001:4860:4860::8888]:53,[2606:4700:4700::1111]:443,[2001:4860:4860::8888]:443 \
     # VPN server filtering
     SERVER_REGIONS= \
     SERVER_COUNTRIES= \
@@ -163,20 +170,23 @@ ENV VPN_SERVICE_PROVIDER=pia \
     LOG_LEVEL=info \
     # Health
     HEALTH_SERVER_ADDRESS=127.0.0.1:9999 \
-    HEALTH_TARGET_ADDRESS=cloudflare.com:443 \
-    HEALTH_SUCCESS_WAIT_DURATION=5s \
-    HEALTH_VPN_DURATION_INITIAL=6s \
-    HEALTH_VPN_DURATION_ADDITION=5s \
-    # DNS over TLS
-    DOT=on \
-    DOT_PROVIDERS=cloudflare \
-    DOT_PRIVATE_ADDRESS=127.0.0.1/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16,169.254.0.0/16,::1/128,fc00::/7,fe80::/10,::ffff:7f00:1/104,::ffff:a00:0/104,::ffff:a9fe:0/112,::ffff:ac10:0/108,::ffff:c0a8:0/112 \
-    DOT_CACHING=on \
-    DOT_IPV6=off \
+    HEALTH_TARGET_ADDRESSES=cloudflare.com:443,github.com:443 \
+    HEALTH_ICMP_TARGET_IPS=1.1.1.1,8.8.8.8 \
+    HEALTH_SMALL_CHECK_TYPE=icmp \
+    HEALTH_RESTART_VPN=on \
+    # DNS
+    DNS_SERVER=on \
+    DNS_UPSTREAM_RESOLVER_TYPE=DoT \
+    DNS_UPSTREAM_RESOLVERS=cloudflare \
+    DNS_BLOCK_IPS= \
+    DNS_BLOCK_IP_PREFIXES= \
+    DNS_CACHING=on \
+    DNS_UPSTREAM_IPV6=off \
     BLOCK_MALICIOUS=on \
     BLOCK_SURVEILLANCE=off \
     BLOCK_ADS=off \
-    UNBLOCK= \
+    DNS_UNBLOCK_HOSTNAMES= \
+    DNS_REBINDING_PROTECTION_EXEMPT_HOSTNAMES= \
     DNS_UPDATE_PERIOD=24h \
     DNS_ADDRESS=127.0.0.1 \
     DNS_KEEP_NAMESERVER=off \
@@ -200,10 +210,13 @@ ENV VPN_SERVICE_PROVIDER=pia \
     HTTP_CONTROL_SERVER_LOG=on \
     HTTP_CONTROL_SERVER_ADDRESS=":8000" \
     HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH=/gluetun/auth/config.toml \
+    HTTP_CONTROL_SERVER_AUTH_DEFAULT_ROLE="{}" \
     # Server data updater
     UPDATER_PERIOD=0 \
     UPDATER_MIN_RATIO=0.8 \
     UPDATER_VPN_SERVICE_PROVIDERS= \
+    UPDATER_PROTONVPN_EMAIL= \
+    UPDATER_PROTONVPN_PASSWORD= \
     # Public IP
     PUBLICIP_FILE="/tmp/gluetun/ip" \
     PUBLICIP_ENABLED=on \
@@ -219,8 +232,8 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Extras
     VERSION_INFORMATION=on \
     TZ= \
-    PUID= \
-    PGID=
+    PUID=1000 \
+    PGID=1000
 ENTRYPOINT ["/gluetun-entrypoint"]
 EXPOSE 8000/tcp 8888/tcp 8388/tcp 8388/udp
 HEALTHCHECK --interval=5s --timeout=5s --start-period=10s --retries=3 CMD /gluetun-entrypoint healthcheck

README.md

@@ -1,6 +1,8 @@
 # Gluetun VPN client
 
-Lightweight swiss-knife-like VPN client to multiple VPN service providers
+⚠️ This and [gluetun-wiki](https://github.com/qdm12/gluetun-wiki) are the only websites for Gluetun, other websites claiming to be official are scams ⚠️
+
+Lightweight swiss-army-knife-like VPN client to multiple VPN service providers
 
 ![Title image](https://raw.githubusercontent.com/qdm12/gluetun/master/title.svg)
 
@@ -26,7 +28,6 @@ Lightweight swiss-knife-like VPN client to multiple VPN service providers
 [![GitHub issues](https://img.shields.io/github/issues/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues)
 [![GitHub closed issues](https://img.shields.io/github/issues-closed/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues?q=is%3Aissue+is%3Aclosed)
 
-[![Lines of code](https://img.shields.io/tokei/lines/github/qdm12/gluetun)](https://github.com/qdm12/gluetun)
 ![Code size](https://img.shields.io/github/languages/code-size/qdm12/gluetun)
 ![GitHub repo size](https://img.shields.io/github/repo-size/qdm12/gluetun)
 ![Go version](https://img.shields.io/github/go-mod/go-version/qdm12/gluetun)
@@ -56,12 +57,12 @@ Lightweight swiss-knife-like VPN client to multiple VPN service providers
 
 ## Features
 
-- Based on Alpine 3.20 for a small Docker image of 35.6MB
-- Supports: **AirVPN**, **Cyberghost**, **ExpressVPN**, **FastestVPN**, **Giganews**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad**, **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **WeVPN**, **Windscribe** servers
+- Based on Alpine 3.22 for a small Docker image of 41.1MB
+- Supports: **AirVPN**, **Cyberghost**, **ExpressVPN**, **FastestVPN**, **Giganews**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad** (Wireguard only), **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **Windscribe** servers
 - Supports OpenVPN for all providers listed
 - Supports Wireguard both kernelspace and userspace
   - For **AirVPN**, **FastestVPN**, **Ivpn**, **Mullvad**, **NordVPN**, **Perfect privacy**, **ProtonVPN**, **Surfshark** and **Windscribe**
-  - For **Cyberghost**, **Private Internet Access**, **PrivateVPN**, **PureVPN**, **Torguard**, **VPN Unlimited**, **VyprVPN** and **WeVPN** using [the custom provider](https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/custom.md)
+  - For **Cyberghost**, **Private Internet Access**, **PrivateVPN**, **PureVPN**, **Torguard**, **VPN Unlimited** and **VyprVPN** using [the custom provider](https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/custom.md)
   - For custom Wireguard configurations using [the custom provider](https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/custom.md)
   - More in progress, see [#134](https://github.com/qdm12/gluetun/issues/134)
 - DNS over TLS baked in with service provider(s) of your choice
@@ -88,7 +89,7 @@ Go to the [Wiki](https://github.com/qdm12/gluetun-wiki)!
 Here's a docker-compose.yml for the laziest:
 
 ```yml
-version: "3"
+---
 services:
   gluetun:
     image: qmcgaw/gluetun
@@ -124,6 +125,10 @@ services:
 
 🆕 Image also available as `ghcr.io/qdm12/gluetun`
 
+## Fun graphs
+
+[![Star History Chart](https://api.star-history.com/svg?repos=qdm12/gluetun&type=date&legend=top-left)](https://www.star-history.com/#qdm12/gluetun&type=date&legend=top-left)
+
 ## License
 
 [![MIT](https://img.shields.io/github/license/qdm12/gluetun)](https://github.com/qdm12/gluetun/blob/master/LICENSE)

ci/cmd/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"github.com/qdm12/gluetun/ci/internal"
+	"github.com/qdm12/log"
+)
+
+func main() {
+	logger := log.New()
+	if len(os.Args) < 2 {
+		logger.Error("Usage: " + os.Args[0] + " <command>")
+		os.Exit(1)
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+
+	var err error
+	switch os.Args[1] {
+	case "mullvad":
+		err = internal.MullvadTest(ctx, logger)
+	case "protonvpn":
+		err = internal.ProtonVPNTest(ctx, logger)
+	default:
+		err = fmt.Errorf("unknown command: %s", os.Args[1])
+	}
+	stop()
+	if err != nil {
+		logger.Error(err.Error())
+		os.Exit(1)
+	}
+	logger.Info("test completed successfully")
+}

ci/go.mod

@@ -0,0 +1,40 @@
+module github.com/qdm12/gluetun/ci
+
+go 1.25.0
+
+require (
+	github.com/docker/docker v28.5.1+incompatible
+	github.com/opencontainers/image-spec v1.1.1
+)
+
+require (
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/containerd/errdefs v1.0.0 // indirect
+	github.com/containerd/errdefs/pkg v0.3.0 // indirect
+	github.com/containerd/log v0.1.0 // indirect
+	github.com/distribution/reference v0.6.0 // indirect
+	github.com/docker/go-connections v0.6.0 // indirect
+	github.com/docker/go-units v0.5.0 // indirect
+	github.com/fatih/color v1.13.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/mattn/go-colorable v0.1.9 // indirect
+	github.com/mattn/go-isatty v0.0.14 // indirect
+	github.com/moby/docker-image-spec v1.3.1 // indirect
+	github.com/moby/sys/atomicwriter v0.1.0 // indirect
+	github.com/moby/term v0.5.2 // indirect
+	github.com/morikuni/aec v1.0.0 // indirect
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/qdm12/log v0.1.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.63.0 // indirect
+	go.opentelemetry.io/otel v1.38.0 // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.38.0 // indirect
+	go.opentelemetry.io/otel/metric v1.38.0 // indirect
+	go.opentelemetry.io/otel/trace v1.38.0 // indirect
+	golang.org/x/sys v0.35.0 // indirect
+	golang.org/x/time v0.14.0 // indirect
+	gotest.tools/v3 v3.5.2 // indirect
+)

ci/go.sum

@@ -0,0 +1,109 @@
+github.com/Azure/go-ansiterm v0.0.0-20250102033503-faa5f7b0171c h1:udKWzYgxTojEKWjV8V+WSxDXJ4NFATAsZjh8iIbsQIg=
+github.com/Azure/go-ansiterm v0.0.0-20250102033503-faa5f7b0171c/go.mod h1:xomTg63KZ2rFqZQzSB4Vz2SUXa1BpHTVz9L5PTmPC4E=
+github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
+github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
+github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
+github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=
+github.com/containerd/errdefs v1.0.0 h1:tg5yIfIlQIrxYtu9ajqY42W3lpS19XqdxRQeEwYG8PI=
+github.com/containerd/errdefs v1.0.0/go.mod h1:+YBYIdtsnF4Iw6nWZhJcqGSg/dwvV7tyJ/kCkyJ2k+M=
+github.com/containerd/errdefs/pkg v0.3.0 h1:9IKJ06FvyNlexW690DXuQNx2KA2cUJXx151Xdx3ZPPE=
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+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
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+google.golang.org/genproto/googleapis/api v0.0.0-20250825161204-c5933d9347a5/go.mod h1:j3QtIyytwqGr1JUDtYXwtMXWPKsEa5LtzIFN1Wn5WvE=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250825161204-c5933d9347a5 h1:eaY8u2EuxbRv7c3NiGK0/NedzVsCcV6hDuU5qPX5EGE=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250825161204-c5933d9347a5/go.mod h1:M4/wBTSeyLxupu3W3tJtOgB14jILAS/XWPSSa3TAlJc=
+google.golang.org/grpc v1.75.0 h1:+TW+dqTd2Biwe6KKfhE5JpiYIBWq865PhKGSXiivqt4=
+google.golang.org/grpc v1.75.0/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
+google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
+google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gotest.tools/v3 v3.5.2 h1:7koQfIKdy+I8UTetycgUqXWSDwpgv193Ka+qRsmBY8Q=
+gotest.tools/v3 v3.5.2/go.mod h1:LtdLGcnqToBH83WByAAi/wiwSFCArdFIUV/xxN4pcjA=

ci/internal/mullvad.go

@@ -0,0 +1,27 @@
+package internal
+
+import (
+	"context"
+	"fmt"
+)
+
+func MullvadTest(ctx context.Context, logger Logger) error {
+	expectedSecrets := []string{
+		"Wireguard private key",
+		"Wireguard address",
+	}
+	secrets, err := readSecrets(ctx, expectedSecrets, logger)
+	if err != nil {
+		return fmt.Errorf("reading secrets: %w", err)
+	}
+
+	env := []string{
+		"VPN_SERVICE_PROVIDER=mullvad",
+		"VPN_TYPE=wireguard",
+		"LOG_LEVEL=debug",
+		"SERVER_COUNTRIES=USA",
+		"WIREGUARD_PRIVATE_KEY=" + secrets[0],
+		"WIREGUARD_ADDRESSES=" + secrets[1],
+	}
+	return simpleTest(ctx, env, logger)
+}

ci/internal/protonvpn.go

@@ -0,0 +1,25 @@
+package internal
+
+import (
+	"context"
+	"fmt"
+)
+
+func ProtonVPNTest(ctx context.Context, logger Logger) error {
+	expectedSecrets := []string{
+		"Wireguard private key",
+	}
+	secrets, err := readSecrets(ctx, expectedSecrets, logger)
+	if err != nil {
+		return fmt.Errorf("reading secrets: %w", err)
+	}
+
+	env := []string{
+		"VPN_SERVICE_PROVIDER=protonvpn",
+		"VPN_TYPE=wireguard",
+		"LOG_LEVEL=debug",
+		"SERVER_COUNTRIES=United States",
+		"WIREGUARD_PRIVATE_KEY=" + secrets[0],
+	}
+	return simpleTest(ctx, env, logger)
+}

ci/internal/secrets.go

@@ -0,0 +1,49 @@
+package internal
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"strings"
+)
+
+type Logger interface {
+	Info(msg string)
+	Infof(format string, args ...any)
+}
+
+func readSecrets(ctx context.Context, expectedSecrets []string,
+	logger Logger,
+) (lines []string, err error) {
+	scanner := bufio.NewScanner(os.Stdin)
+	lines = make([]string, 0, len(expectedSecrets))
+
+	for i := range expectedSecrets {
+		logger.Infof("🤫 reading %s from Stdin...", expectedSecrets[i])
+		if !scanner.Scan() {
+			break
+		}
+		lines = append(lines, strings.TrimSpace(scanner.Text()))
+		logger.Infof("🤫 %s secret read successfully", expectedSecrets[i])
+		if ctx.Err() != nil {
+			return nil, ctx.Err()
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("reading secrets from stdin: %w", err)
+	}
+
+	if len(lines) < len(expectedSecrets) {
+		return nil, fmt.Errorf("expected %d secrets via Stdin, but only received %d",
+			len(expectedSecrets), len(lines))
+	}
+	for i, line := range lines {
+		if line == "" {
+			return nil, fmt.Errorf("secret on line %d/%d was empty", i+1, len(lines))
+		}
+	}
+
+	return lines, nil
+}

ci/internal/simple.go

@@ -0,0 +1,134 @@
+package internal
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"regexp"
+	"time"
+
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/api/types/network"
+	"github.com/docker/docker/client"
+	v1 "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+func ptrTo[T any](v T) *T { return &v }
+
+func simpleTest(ctx context.Context, env []string, logger Logger) error {
+	const timeout = 30 * time.Second
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	client, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
+	if err != nil {
+		return fmt.Errorf("creating Docker client: %w", err)
+	}
+	defer client.Close()
+
+	config := &container.Config{
+		Image:       "qmcgaw/gluetun",
+		StopTimeout: ptrTo(3),
+		Env:         env,
+	}
+	hostConfig := &container.HostConfig{
+		AutoRemove: true,
+		CapAdd:     []string{"NET_ADMIN", "NET_RAW"},
+	}
+	networkConfig := (*network.NetworkingConfig)(nil)
+	platform := (*v1.Platform)(nil)
+	const containerName = "" // auto-generated name
+
+	response, err := client.ContainerCreate(ctx, config, hostConfig, networkConfig, platform, containerName)
+	if err != nil {
+		return fmt.Errorf("creating container: %w", err)
+	}
+	for _, warning := range response.Warnings {
+		fmt.Println("Warning during container creation:", warning)
+	}
+	containerID := response.ID
+	defer stopContainer(client, containerID)
+
+	beforeStartTime := time.Now()
+
+	err = client.ContainerStart(ctx, containerID, container.StartOptions{})
+	if err != nil {
+		return fmt.Errorf("starting container: %w", err)
+	}
+
+	return waitForLogLine(ctx, client, containerID, beforeStartTime, logger)
+}
+
+func stopContainer(client *client.Client, containerID string) {
+	const stopTimeout = 5 * time.Second // must be higher than 3s, see above [container.Config]'s StopTimeout field
+	stopCtx, stopCancel := context.WithTimeout(context.Background(), stopTimeout)
+	defer stopCancel()
+
+	err := client.ContainerStop(stopCtx, containerID, container.StopOptions{})
+	if err != nil {
+		fmt.Println("failed to stop container:", err)
+	}
+}
+
+var successRegexp = regexp.MustCompile(`^.+Public IP address is .+$`)
+
+func waitForLogLine(ctx context.Context, client *client.Client, containerID string,
+	beforeStartTime time.Time, logger Logger,
+) error {
+	logOptions := container.LogsOptions{
+		ShowStdout: true,
+		Follow:     true,
+		Since:      beforeStartTime.Format(time.RFC3339Nano),
+	}
+
+	reader, err := client.ContainerLogs(ctx, containerID, logOptions)
+	if err != nil {
+		return fmt.Errorf("error getting container logs: %w", err)
+	}
+	defer reader.Close()
+
+	var linesSeen []string
+	scanner := bufio.NewScanner(reader)
+	for ctx.Err() == nil {
+		if scanner.Scan() {
+			line := scanner.Text()
+			if len(line) > 8 { // remove Docker log prefix
+				line = line[8:]
+			}
+			linesSeen = append(linesSeen, line)
+			if successRegexp.MatchString(line) {
+				fmt.Println("✅ Success line logged")
+				return nil
+			}
+			continue
+		}
+		err := scanner.Err()
+		if err != nil && err != io.EOF {
+			logSeenLines(logger, linesSeen)
+			return fmt.Errorf("reading log stream: %w", err)
+		}
+
+		// The scanner is either done or cannot read because of EOF
+		logger.Info("the log scanner stopped")
+		logSeenLines(logger, linesSeen)
+
+		// Check if the container is still running
+		inspect, err := client.ContainerInspect(ctx, containerID)
+		if err != nil {
+			return fmt.Errorf("inspecting container: %w", err)
+		}
+		if !inspect.State.Running {
+			return fmt.Errorf("container stopped unexpectedly while waiting for log line. Exit code: %d", inspect.State.ExitCode)
+		}
+	}
+
+	return ctx.Err()
+}
+
+func logSeenLines(logger Logger, lines []string) {
+	fmt.Println("Logs seen so far:")
+	for _, line := range lines {
+		fmt.Println("  " + line)
+	}
+}

cmd/gluetun/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/fs"
 	"net/http"
+	"net/netip"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -22,6 +23,7 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/sources/files"
 	"github.com/qdm12/gluetun/internal/configuration/sources/secrets"
 	"github.com/qdm12/gluetun/internal/constants"
+	copenvpn "github.com/qdm12/gluetun/internal/constants/openvpn"
 	"github.com/qdm12/gluetun/internal/dns"
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/gluetun/internal/healthcheck"
@@ -164,7 +166,9 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		}
 	}
 
-	announcementExp, err := time.Parse(time.RFC3339, "2024-12-01T00:00:00Z")
+	defer fmt.Println(gluetunLogo)
+
+	announcementExp, err := time.Parse(time.RFC3339, "2026-04-01T00:00:00Z")
 	if err != nil {
 		return err
 	}
@@ -175,7 +179,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		Version:      buildInfo.Version,
 		Commit:       buildInfo.Commit,
 		Created:      buildInfo.Created,
-		Announcement: "All control server routes will become private by default after the v3.41.0 release",
+		Announcement: "All control server routes are now private by default",
 		AnnounceExp:  announcementExp,
 		// Sponsor information
 		PaypalUser:    "qmcgaw",
@@ -233,6 +237,10 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		if err != nil {
 			return err
 		}
+		err = netLinker.FlushConntrack()
+		if err != nil {
+			logger.Warnf("flushing conntrack failed: %s", err)
+		}
 	}
 
 	// TODO run this in a loop or in openvpn to reload from file without restarting
@@ -260,19 +268,22 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	puid, pgid := int(*allSettings.System.PUID), int(*allSettings.System.PGID)
 
-	const clientTimeout = 15 * time.Second
+	const clientTimeout = 35 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
 	// Create configurators
 	alpineConf := alpine.New()
 	ovpnConf := openvpn.New(
 		logger.New(log.SetComponent("openvpn configurator")),
 		cmder, puid, pgid)
+	ovpnVersion := ovpnConf.Version26
+	if allSettings.VPN.OpenVPN.Version == copenvpn.Openvpn25 {
+		ovpnVersion = ovpnConf.Version25
+	}
 
 	err = printVersions(ctx, logger, []printVersionElement{
 		{name: "Alpine", getVersion: alpineConf.Version},
-		{name: "OpenVPN 2.5", getVersion: ovpnConf.Version25},
-		{name: "OpenVPN 2.6", getVersion: ovpnConf.Version26},
-		{name: "IPtables", getVersion: firewallConf.Version},
+		{name: "OpenVPN", getVersion: ovpnVersion},
+		{name: "Firewall", getVersion: firewallConf.Version},
 	})
 	if err != nil {
 		return err
@@ -414,18 +425,26 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		return fmt.Errorf("starting public ip loop: %w", err)
 	}
 
+	healthLogger := logger.New(log.SetComponent("healthcheck"))
+	healthcheckServer := healthcheck.NewServer(allSettings.Health, healthLogger)
+	healthServerHandler, healthServerCtx, healthServerDone := goshutdown.NewGoRoutineHandler(
+		"HTTP health server", goroutine.OptionTimeout(defaultShutdownTimeout))
+	go healthcheckServer.Run(healthServerCtx, healthServerDone)
+	healthChecker := healthcheck.NewChecker(healthLogger)
+
 	updaterLogger := logger.New(log.SetComponent("updater"))
 
 	unzipper := unzip.New(httpClient)
 	parallelResolver := resolver.NewParallelResolver(allSettings.Updater.DNSAddress)
 	openvpnFileExtractor := extract.New()
 	providers := provider.NewProviders(storage, time.Now, updaterLogger,
-		httpClient, unzipper, parallelResolver, publicIPLooper.Fetcher(), openvpnFileExtractor)
+		httpClient, unzipper, parallelResolver, publicIPLooper.Fetcher(),
+		openvpnFileExtractor, allSettings.Updater)
 
 	vpnLogger := logger.New(log.SetComponent("vpn"))
 	vpnLooper := vpn.NewLoop(allSettings.VPN, ipv6Supported, allSettings.Firewall.VPNInputPorts,
-		providers, storage, ovpnConf, netLinker, firewallConf, routingConf, portForwardLooper,
-		cmder, publicIPLooper, dnsLooper, vpnLogger, httpClient,
+		providers, storage, allSettings.Health, healthChecker, healthcheckServer, ovpnConf, netLinker, firewallConf,
+		routingConf, portForwardLooper, cmder, publicIPLooper, dnsLooper, vpnLogger, httpClient,
 		buildInfo, *allSettings.Version.Enabled)
 	vpnHandler, vpnCtx, vpnDone := goshutdown.NewGoRoutineHandler(
 		"vpn", goroutine.OptionTimeout(time.Second))
@@ -459,13 +478,10 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	go shadowsocksLooper.Run(shadowsocksCtx, shadowsocksDone)
 	otherGroupHandler.Add(shadowsocksHandler)
 
-	controlServerAddress := *allSettings.ControlServer.Address
-	controlServerLogging := *allSettings.ControlServer.Log
 	httpServerHandler, httpServerCtx, httpServerDone := goshutdown.NewGoRoutineHandler(
 		"http server", goroutine.OptionTimeout(defaultShutdownTimeout))
-	httpServer, err := server.New(httpServerCtx, controlServerAddress, controlServerLogging,
+	httpServer, err := server.New(httpServerCtx, allSettings.ControlServer,
 		logger.New(log.SetComponent("http server")),
-		allSettings.ControlServer.AuthFilePath,
 		buildInfo, vpnLooper, portForwardLooper, dnsLooper, updaterLooper, publicIPLooper,
 		storage, ipv6Supported)
 	if err != nil {
@@ -476,12 +492,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	<-httpServerReady
 	controlGroupHandler.Add(httpServerHandler)
 
-	healthLogger := logger.New(log.SetComponent("healthcheck"))
-	healthcheckServer := healthcheck.NewServer(allSettings.Health, healthLogger, vpnLooper)
-	healthServerHandler, healthServerCtx, healthServerDone := goshutdown.NewGoRoutineHandler(
-		"HTTP health server", goroutine.OptionTimeout(defaultShutdownTimeout))
-	go healthcheckServer.Run(healthServerCtx, healthServerDone)
-
 	orderHandler := goshutdown.NewOrderHandler("gluetun",
 		order.OptionTimeout(totalShutdownTimeout),
 		order.OptionOnSuccess(defaultShutdownOnSuccess),
@@ -550,24 +560,25 @@ type netLinker interface {
 	Linker
 	IsWireguardSupported() (ok bool, err error)
 	IsIPv6Supported() (ok bool, err error)
+	FlushConntrack() error
 	PatchLoggerLevel(level log.Level)
 }
 
 type Addresser interface {
-	AddrList(link netlink.Link, family int) (
-		addresses []netlink.Addr, err error)
-	AddrReplace(link netlink.Link, addr netlink.Addr) error
+	AddrList(linkIndex uint32, family uint8) (
+		addresses []netip.Prefix, err error)
+	AddrReplace(linkIndex uint32, addr netip.Prefix) error
 }
 
 type Router interface {
-	RouteList(family int) (routes []netlink.Route, err error)
+	RouteList(family uint8) (routes []netlink.Route, err error)
 	RouteAdd(route netlink.Route) error
 	RouteDel(route netlink.Route) error
 	RouteReplace(route netlink.Route) error
 }
 
 type Ruler interface {
-	RuleList(family int) (rules []netlink.Rule, err error)
+	RuleList(family uint8) (rules []netlink.Rule, err error)
 	RuleAdd(rule netlink.Rule) error
 	RuleDel(rule netlink.Rule) error
 }
@@ -575,11 +586,12 @@ type Ruler interface {
 type Linker interface {
 	LinkList() (links []netlink.Link, err error)
 	LinkByName(name string) (link netlink.Link, err error)
-	LinkByIndex(index int) (link netlink.Link, err error)
-	LinkAdd(link netlink.Link) (linkIndex int, err error)
-	LinkDel(link netlink.Link) (err error)
-	LinkSetUp(link netlink.Link) (linkIndex int, err error)
-	LinkSetDown(link netlink.Link) (err error)
+	LinkByIndex(index uint32) (link netlink.Link, err error)
+	LinkAdd(link netlink.Link) (linkIndex uint32, err error)
+	LinkDel(linkIndex uint32) (err error)
+	LinkSetUp(linkIndex uint32) (err error)
+	LinkSetDown(linkIndex uint32) (err error)
+	LinkSetMTU(linkIndex, mtu uint32) error
 }
 
 type clier interface {
@@ -601,3 +613,34 @@ type RunStarter interface {
 	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,
 		waitError <-chan error, err error)
 }
+
+const gluetunLogo = `                         @@@
+                         @@@@
+                        @@@@@@
+                       @@@@.@@                       @@@@@@@@@@
+                       @@@@.@@@                   @@@@@@@@==@@@@
+                      @@@.@..@@                @@@@@@@=@..==@@@@
+            @@@@      @@@.@@.@@              @@@@@@===@@@@.=@@@
+           @...-@@   @@@@.@@.@@@  @@@     @@@@@@=======@@@=@@@@
+           @@@@@@@@  @@@.-%@.+@@@@@@@@  @@@@@%============@@@@
+                     @@@.--@..@@@@.-@@@@@@@==============@@@@
+              @@@@  @@@-@--@@.@@.---@@@@@==============#@@@@@
+              @@@   @@@.@@-@@.@@--@@@@@===============@@@@@@
+                   @@@@.@--@@@@@@@@@@================@@@@@@@
+                   @@@..--@@*@@@@@@================@@@@+*@@
+                   @@@.---@@.@@@@=================@@@@--@@
+                  @@@-.---@@@@@@================@@@@*--@@@
+                  @@@.:-#@@@@@@===============*@@@@.---@@
+                  @@@.-------.@@@============@@@@@@.--@@@
+                 @@@..--------:@@@=========@@@@@@@@.--@@@
+                 @@@.-@@@@@@@@@@@========@@@@@  @@@.--@@
+                 @@.@@@@===============@@@@@ @@@@@@---@@@@@@
+                @@@@@@@==============@@@@@@@@@@@@*@---@@@@@@@@
+                @@@@@@=============@@@@@ @@@...------------.*@@@
+                @@@@%===========@@@@@@ @@@..------@@@@.-----.-@@@
+                @@@@@@.=======@@@@@@  @@@.-------@@@@@@-.------=@@
+               @@@@@@@@@===@@@@@@     @@.------@@@@   @@@@.-----@@@
+               @@@==@@@=@@@@@@@      @@@.-@@@@@@@       @@@@@@@--@@
+               @@@@@@@@@@@@@         @@@@@@@@                @@@@@@@
+                @@@@@@@@             @@@@                       @@@@
+                                                                       `

go.mod

@@ -1,59 +1,66 @@
 module github.com/qdm12/gluetun
 
-go 1.23
+go 1.25.0
 
 require (
-	github.com/breml/rootcerts v0.2.19
+	github.com/ProtonMail/go-srp v0.0.7
+	github.com/breml/rootcerts v0.3.4
 	github.com/fatih/color v1.18.0
 	github.com/golang/mock v1.6.0
-	github.com/klauspost/compress v1.17.11
+	github.com/google/nftables v0.3.0
+	github.com/jsimonetti/rtnetlink v1.4.2
+	github.com/klauspost/compress v1.18.1
 	github.com/klauspost/pgzip v1.2.6
-	github.com/pelletier/go-toml/v2 v2.2.3
-	github.com/qdm12/dns/v2 v2.0.0-rc8
+	github.com/mdlayher/genetlink v1.3.2
+	github.com/mdlayher/netlink v1.7.3-0.20250113171957-fbb4dce95f42
+	github.com/pelletier/go-toml/v2 v2.2.4
+	github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260216151239-36b3306f2205
 	github.com/qdm12/gosettings v0.4.4
 	github.com/qdm12/goshutdown v0.3.0
 	github.com/qdm12/gosplash v0.2.0
 	github.com/qdm12/gotree v0.3.0
 	github.com/qdm12/log v0.1.0
 	github.com/qdm12/ss-server v0.6.0
-	github.com/stretchr/testify v1.10.0
-	github.com/ulikunitz/xz v0.5.11
-	github.com/vishvananda/netlink v1.2.1
+	github.com/stretchr/testify v1.11.1
+	github.com/ti-mo/netfilter v0.5.3
+	github.com/ulikunitz/xz v0.5.15
 	github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a
 	golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c
-	golang.org/x/net v0.31.0
-	golang.org/x/sys v0.27.0
-	golang.org/x/text v0.20.0
+	golang.org/x/net v0.49.0
+	golang.org/x/sys v0.40.0
+	golang.org/x/text v0.33.0
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230429144221-925a1e7659e6
 	gopkg.in/ini.v1 v1.67.0
 )
 
 require (
+	github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf // indirect
+	github.com/ProtonMail/go-crypto v1.3.0-proton // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/cronokirby/saferith v0.33.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/google/go-cmp v0.6.0 // indirect
-	github.com/josharian/native v1.1.0 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mdlayher/genetlink v1.3.2 // indirect
-	github.com/mdlayher/netlink v1.7.2 // indirect
-	github.com/mdlayher/socket v0.4.1 // indirect
+	github.com/mdlayher/socket v0.5.1 // indirect
 	github.com/miekg/dns v1.1.62 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.20.5 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
 	github.com/prometheus/common v0.60.1 // indirect
 	github.com/prometheus/procfs v0.15.1 // indirect
-	github.com/qdm12/goservices v0.1.0 // indirect
+	github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978 // indirect
 	github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 // indirect
-	github.com/vishvananda/netns v0.0.4 // indirect
-	golang.org/x/crypto v0.29.0 // indirect
-	golang.org/x/mod v0.21.0 // indirect
-	golang.org/x/sync v0.9.0 // indirect
-	golang.org/x/tools v0.26.0 // indirect
+	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/mod v0.31.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/time v0.3.0 // indirect
+	golang.org/x/tools v0.40.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	google.golang.org/protobuf v1.35.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -1,9 +1,25 @@
+github.com/ProtonMail/bcrypt v0.0.0-20210511135022-227b4adcab57/go.mod h1:HecWFHognK8GfRDGnFQbW/LiV7A3MX3gZVs45vk5h8I=
+github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf h1:yc9daCCYUefEs69zUkSzubzjBbL+cmOXgnmt9Fyd9ug=
+github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf/go.mod h1:o0ESU9p83twszAU8LBeJKFAAMX14tISa0yk4Oo5TOqo=
+github.com/ProtonMail/go-crypto v0.0.0-20230321155629-9a39f2531310/go.mod h1:8TI4H3IbrackdNgv+92dI+rhpCaLqM0IfpgCgenFvRE=
+github.com/ProtonMail/go-crypto v1.3.0-proton h1:tAQKQRZX/73VmzK6yHSCaRUOvS/3OYSQzhXQsrR7yUM=
+github.com/ProtonMail/go-crypto v1.3.0-proton/go.mod h1:9whxjD8Rbs29b4XWbB8irEcE8KHMqaR2e7GWU1R+/PE=
+github.com/ProtonMail/go-srp v0.0.7 h1:Sos3Qk+th4tQR64vsxGIxYpN3rdnG9Wf9K4ZloC1JrI=
+github.com/ProtonMail/go-srp v0.0.7/go.mod h1:giCp+7qRnMIcCvI6V6U3S1lDDXDQYx2ewJ6F/9wdlJk=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/breml/rootcerts v0.2.19 h1:3D/qwAC1xoh82GmZ21mYzQ1NaLOICUVntIo+MRZYr4U=
-github.com/breml/rootcerts v0.2.19/go.mod h1:S/PKh+4d1HUn4HQovEB8hPJZO6pUZYrIhmXBhsegfXw=
+github.com/breml/rootcerts v0.3.4 h1:9i7WNl/ctd9OEAOaTfLy//Wrlfxq/tRQ7v4okYFN9Ys=
+github.com/breml/rootcerts v0.3.4/go.mod h1:S/PKh+4d1HUn4HQovEB8hPJZO6pUZYrIhmXBhsegfXw=
+github.com/bwesterb/go-ristretto v1.2.0/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7NFEuV9ekS419A0=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cilium/ebpf v0.12.3 h1:8ht6F9MquybnY97at+VDZb3eQQr8ev79RueWeVaEcG4=
+github.com/cilium/ebpf v0.12.3/go.mod h1:TctK1ivibvI3znr66ljgi4hqOT8EYQjz1KWBfb1UVgM=
+github.com/cloudflare/circl v1.1.0/go.mod h1:prBCrKB9DV4poKZY1l9zBXg2QJY7mvgRvtMxxK7fi4I=
+github.com/cloudflare/circl v1.6.1 h1:zqIqSPIndyBh1bjLVVDHMPpVKqp8Su/V+6MeDzzQBQ0=
+github.com/cloudflare/circl v1.6.1/go.mod h1:uddAzsPgqdMAYatqJ0lsjX1oECcQLIlRpzZh3pJrofs=
+github.com/cronokirby/saferith v0.33.0 h1:TgoQlfsD4LIwx71+ChfRcIpjkw+RPOapDEVxa+LhwLo=
+github.com/cronokirby/saferith v0.33.0/go.mod h1:QKJhjoqUtBsXCAVEjw38mFqoi7DebT7kthcD7UzbnoA=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
@@ -12,12 +28,14 @@ github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
 github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
 github.com/google/btree v1.0.1 h1:gK4Kx5IaGY9CD5sPJ36FHiBJ6ZXl0kilRiiCj+jdYp4=
 github.com/google/btree v1.0.1/go.mod h1:xXMiIv4Fb/0kKde4SpL7qlzvu5cMJDRkFDxJfI9uaxA=
-github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
-github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/josharian/native v1.1.0 h1:uuaP0hAbW7Y4l0ZRQ6C9zfb7Mg1mbFKry/xzDAfmtLA=
-github.com/josharian/native v1.1.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
-github.com/klauspost/compress v1.17.11 h1:In6xLpyWOi1+C7tXUUWv2ot1QvBjxevKAaI6IXrJmUc=
-github.com/klauspost/compress v1.17.11/go.mod h1:pMDklpSncoRMuLFrf1W9Ss9KT+0rH90U12bZKk7uwG0=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
+github.com/google/nftables v0.3.0 h1:bkyZ0cbpVeMHXOrtlFc8ISmfVqq5gPJukoYieyVmITg=
+github.com/google/nftables v0.3.0/go.mod h1:BCp9FsrbF1Fn/Yu6CLUc9GGZFw/+hsxfluNXXmxBfRM=
+github.com/jsimonetti/rtnetlink v1.4.2 h1:Df9w9TZ3npHTyDn0Ev9e1uzmN2odmXd0QX+J5GTEn90=
+github.com/jsimonetti/rtnetlink v1.4.2/go.mod h1:92s6LJdE+1iOrw+F2/RO7LYI2Qd8pPpFNNUYW06gcoM=
+github.com/klauspost/compress v1.18.1 h1:bcSGx7UbpBqMChDtsF28Lw6v/G94LPrrbMbdC3JH2co=
+github.com/klauspost/compress v1.18.1/go.mod h1:ZQFFVG+MdnR0P+l6wpXgIL4NTtwiKIdBnrBd8Nrxr+0=
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
 github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -31,18 +49,20 @@ github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWE
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mdlayher/genetlink v1.3.2 h1:KdrNKe+CTu+IbZnm/GVUMXSqBBLqcGpRDa0xkQy56gw=
 github.com/mdlayher/genetlink v1.3.2/go.mod h1:tcC3pkCrPUGIKKsCsp0B3AdaaKuHtaxoJRz3cc+528o=
-github.com/mdlayher/netlink v1.7.2 h1:/UtM3ofJap7Vl4QWCPDGXY8d3GIY2UGSDbK+QWmY8/g=
-github.com/mdlayher/netlink v1.7.2/go.mod h1:xraEF7uJbxLhc5fpHL4cPe221LI2bdttWlU+ZGLfQSw=
-github.com/mdlayher/socket v0.4.1 h1:eM9y2/jlbs1M615oshPQOHZzj6R6wMT7bX5NPiQvn2U=
-github.com/mdlayher/socket v0.4.1/go.mod h1:cAqeGjoufqdxWkD7DkpyS+wcefOtmu5OQ8KuoJGIReA=
+github.com/mdlayher/netlink v1.7.3-0.20250113171957-fbb4dce95f42 h1:A1Cq6Ysb0GM0tpKMbdCXCIfBclan4oHk1Jb+Hrejirg=
+github.com/mdlayher/netlink v1.7.3-0.20250113171957-fbb4dce95f42/go.mod h1:BB4YCPDOzfy7FniQ/lxuYQ3dgmM2cZumHbK8RpTjN2o=
+github.com/mdlayher/socket v0.5.1 h1:VZaqt6RkGkt2OE9l3GcC6nZkqD3xKeQLyfleW/uBcos=
+github.com/mdlayher/socket v0.5.1/go.mod h1:TjPLHI1UgwEv5J1B5q0zTZq12A/6H7nKmtTanQE37IQ=
 github.com/miekg/dns v1.1.62 h1:cN8OuEF1/x5Rq6Np+h1epln8OiyPWV+lROx9LxcGgIQ=
 github.com/miekg/dns v1.1.62/go.mod h1:mvDlcItzm+br7MToIKqkglaGhlFMHJ9DTNNWONWXbNQ=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721 h1:RlZweED6sbSArvlE924+mUcZuXKLBHA35U7LN621Bws=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721/go.mod h1:Ickgr2WtCLZ2MDGd4Gr0geeCH5HybhRJbonOgQpvSxc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/pelletier/go-toml/v2 v2.2.3 h1:YmeHyLY8mFWbdkNWwpr+qIL2bEqT0o95WSdkNHvL12M=
-github.com/pelletier/go-toml/v2 v2.2.3/go.mod h1:MfCQTFTvCcUyyvvwm1+G6H/jORL20Xlb6rzQu9GuUkc=
+github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
+github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+bR9r+8l63Y=
@@ -53,10 +73,10 @@ github.com/prometheus/common v0.60.1 h1:FUas6GcOw66yB/73KC+BOZoFJmbo/1pojoILArPA
 github.com/prometheus/common v0.60.1/go.mod h1:h0LYf1R1deLSKtD4Vdg8gy4RuOvENW2J/h19V5NADQw=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
-github.com/qdm12/dns/v2 v2.0.0-rc8 h1:kbgKPkbT+79nScfuZ0ZcVhksTGo8IUqQ8TTQGnQlZ18=
-github.com/qdm12/dns/v2 v2.0.0-rc8/go.mod h1:VaF02KWEL7xNV4oKfG4N9nEv/kR6bqyIcBReCV5NJhw=
-github.com/qdm12/goservices v0.1.0 h1:9sODefm/yuIGS7ynCkEnNlMTAYn9GzPhtcK4F69JWvc=
-github.com/qdm12/goservices v0.1.0/go.mod h1:/JOFsAnHFiSjyoXxa5FlfX903h20K5u/3rLzCjYVMck=
+github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260216151239-36b3306f2205 h1:0ycKUDQ50cYb2QpeyGcEnvVs9HJmC9jsb/XZNC1z28c=
+github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260216151239-36b3306f2205/go.mod h1:98foWgXJZ+g8gJIuO+fdO+oWpFei5WShMFTeN4Im2lE=
+github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978 h1:TRGpCU1l0lNwtogEUSs5U+RFceYxkAJUmrGabno7J5c=
+github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978/go.mod h1:D1Po4CRQLYjccnAR2JsVlN1sBMgQrcNLONbvyuzcdTg=
 github.com/qdm12/gosettings v0.4.4 h1:SM6tOZDf6k8qbjWU8KWyBF4mWIixfsKCfh9DGRLHlj4=
 github.com/qdm12/gosettings v0.4.4/go.mod h1:CPrt2YC4UsURTrslmhxocVhMCW03lIrqdH2hzIf5prg=
 github.com/qdm12/goshutdown v0.3.0 h1:pqBpJkdwlZlfTEx4QHtS8u8CXx6pG0fVo6S1N0MpSEM=
@@ -73,59 +93,81 @@ github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 h1:f/FNXud6gA3MNr
 github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3/go.mod h1:HgjTstvQsPGkxUsCd2KWxErBblirPizecHcpD3ffK+s=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
-github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
-github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/ulikunitz/xz v0.5.11 h1:kpFauv27b6ynzBNT/Xy+1k+fK4WswhN/6PN5WhFAGw8=
-github.com/ulikunitz/xz v0.5.11/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
-github.com/vishvananda/netlink v1.2.1 h1:pfLv/qlJUwOTPvtWREA7c3PI4u81YkqZw1DYhI2HmLA=
-github.com/vishvananda/netlink v1.2.1/go.mod h1:i6NetklAujEcC6fK0JPjT8qSwWyO0HLn4UKG+hGqeJs=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+github.com/ti-mo/netfilter v0.5.3 h1:ikzduvnaUMwre5bhbNwWOd6bjqLMVb33vv0XXbK0xGQ=
+github.com/ti-mo/netfilter v0.5.3/go.mod h1:08SyBCg6hu1qyQk4s3DjjJKNrm3RTb32nm6AzyT972E=
+github.com/ulikunitz/xz v0.5.15 h1:9DNdB5s+SgV3bQ2ApL10xRc35ck0DuIX/isZvIk+ubY=
+github.com/ulikunitz/xz v0.5.15/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 github.com/vishvananda/netns v0.0.4 h1:Oeaw1EM2JMxD51g9uhtC0D7erkIjgmj8+JZc26m1YX8=
 github.com/vishvananda/netns v0.0.4/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
 github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a h1:fZHgsYlfvtyqToslyjUt3VOPF4J7aK/3MPcK7xp3PDk=
 github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a/go.mod h1:ul22v+Nro/R083muKhosV54bj5niojjWZvU8xrevuH4=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.29.0 h1:L5SG1JTTXupVV3n6sUqMTeWbjAyfPwoda2DLX8J8FrQ=
-golang.org/x/crypto v0.29.0/go.mod h1:+F4F4N5hv6v38hfeYwTdx20oUvLLc+QfrE9Ax9HtgRg=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
+golang.org/x/crypto v0.47.0 h1:V6e3FRj+n4dbpw86FJ8Fv7XVOql7TEwpHapKoMJ/GO8=
+golang.org/x/crypto v0.47.0/go.mod h1:ff3Y9VzzKbwSSEzWqJsJVBnWmRwRSHt/6Op5n9bQc4A=
 golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c h1:7dEasQXItcW1xKJ2+gg5VOiBnqWrJc+rq0DPKyvvdbY=
 golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c/go.mod h1:NQtJDoLvd6faHhE7m4T/1IY708gDefGGjR/iUW8yQQ8=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
-golang.org/x/mod v0.21.0 h1:vvrHzRwRfVKSiLrG+d4FMl/Qi4ukBCE6kZlTUkDYRT0=
-golang.org/x/mod v0.21.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.31.0 h1:HaW9xtz0+kOcWKwli0ZXy79Ix+UW/vOfmWI5QVd2tgI=
+golang.org/x/mod v0.31.0/go.mod h1:43JraMp9cGx1Rx3AqioxrbrhNsLl2l/iNAvuBkrezpg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
-golang.org/x/net v0.31.0 h1:68CPQngjLL0r2AlUKiSxtQFKvzRVbnzLwMUn5SzcLHo=
-golang.org/x/net v0.31.0/go.mod h1:P4fl1q7dY2hnZFxEk4pPSkDHF+QqjitcnDjUQyMM+pM=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
+golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
+golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.9.0 h1:fEo0HyrW1GIgZdpbhCRO0PkJajUS5H9IFUztCgEo2jQ=
-golang.org/x/sync v0.9.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
+golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
-golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
+golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
+golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.20.0 h1:gK/Kv2otX8gz+wn7Rmb3vT96ZwuoxnQlY+HlJVj7Qug=
-golang.org/x/text v0.20.0/go.mod h1:D4IsuqiFMhST5bX19pQ9ikHC2GsaKyk/oF+pn3ducp4=
-golang.org/x/time v0.0.0-20220210224613-90d013bbcef8 h1:vVKdlvoWBphwdxWKrFZEuM0kGgGLxUOYcY4U/2Vjg44=
-golang.org/x/time v0.0.0-20220210224613-90d013bbcef8/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/text v0.33.0 h1:B3njUFyqtHDUI5jMn1YIr5B0IE2U0qck04r6d4KPAxE=
+golang.org/x/text v0.33.0/go.mod h1:LuMebE6+rBincTi9+xWTY8TztLzKHc/9C1uBCG27+q8=
+golang.org/x/time v0.3.0 h1:rg5rLMjNzMS1RkNLzCG38eapWhnYLFYXDXj2gOlr8j4=
+golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
-golang.org/x/tools v0.26.0 h1:v/60pFQmzmT9ExmjDv2gGIfi3OqfKoEP6I5+umXlbnQ=
-golang.org/x/tools v0.26.0/go.mod h1:TPVVj70c7JJ3WCazhD8OdXcZg/og+b9+tH/KxylGwH0=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/tools v0.40.0 h1:yLkxfA+Qnul4cs9QA3KnlFu0lVmd8JJfoq+E41uSutA=
+golang.org/x/tools v0.40.0/go.mod h1:Ik/tzLRlbscWpqqMRjyWYDisX8bG13FrdXp3o4Sr9lc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

internal/cli/nooplogger.go

@@ -7,3 +7,4 @@ func newNoopLogger() *noopLogger {
 }
 
 func (l *noopLogger) Info(string) {}
+func (l *noopLogger) Warn(string) {}

internal/cli/openvpnconfig.go

@@ -56,6 +56,7 @@ func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, reader *reader.Reader,
 	if err != nil {
 		return err
 	}
+	allSettings.SetDefaults()
 
 	ipv6Supported, err := ipv6Checker.IsIPv6Supported()
 	if err != nil {
@@ -75,7 +76,7 @@ func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, reader *reader.Reader,
 	openvpnFileExtractor := extract.New()
 
 	providers := provider.NewProviders(storage, time.Now, warner, client,
-		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
+		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor, allSettings.Updater)
 	providerConf := providers.Get(allSettings.VPN.Provider.Name)
 	connection, err := providerConf.GetConnection(
 		allSettings.VPN.Provider.ServerSelection, ipv6Supported)

internal/cli/update.go

@@ -6,6 +6,7 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
+	"slices"
 	"strings"
 	"time"
 
@@ -24,6 +25,8 @@ import (
 var (
 	ErrModeUnspecified     = errors.New("at least one of -enduser or -maintainer must be specified")
 	ErrNoProviderSpecified = errors.New("no provider was specified")
+	ErrUsernameMissing     = errors.New("username is required for this provider")
+	ErrPasswordMissing     = errors.New("password is required for this provider")
 )
 
 type UpdaterLogger interface {
@@ -35,7 +38,7 @@ type UpdaterLogger interface {
 func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) error {
 	options := settings.Updater{}
 	var endUserMode, maintainerMode, updateAll bool
-	var csvProviders, ipToken string
+	var csvProviders, ipToken, protonUsername, protonEmail, protonPassword string
 	flagSet := flag.NewFlagSet("update", flag.ExitOnError)
 	flagSet.BoolVar(&endUserMode, "enduser", false, "Write results to /gluetun/servers.json (for end users)")
 	flagSet.BoolVar(&maintainerMode, "maintainer", false,
@@ -47,6 +50,10 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	flagSet.BoolVar(&updateAll, "all", false, "Update servers for all VPN providers")
 	flagSet.StringVar(&csvProviders, "providers", "", "CSV string of VPN providers to update server data for")
 	flagSet.StringVar(&ipToken, "ip-token", "", "IP data service token (e.g. ipinfo.io) to use")
+	flagSet.StringVar(&protonUsername, "proton-username", "",
+		"(Retro-compatibility) Username to use to authenticate with Proton. Use -proton-email instead.") // v4 remove this
+	flagSet.StringVar(&protonEmail, "proton-email", "", "Email to use to authenticate with Proton")
+	flagSet.StringVar(&protonPassword, "proton-password", "", "Password to use to authenticate with Proton")
 	if err := flagSet.Parse(args); err != nil {
 		return err
 	}
@@ -64,6 +71,16 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		options.Providers = strings.Split(csvProviders, ",")
 	}
 
+	if slices.Contains(options.Providers, providers.Protonvpn) {
+		if protonEmail == "" && protonUsername != "" {
+			protonEmail = protonUsername + "@protonmail.com"
+			logger.Warn("use -proton-email instead of -proton-username in the future. " +
+				"This assumes the email is " + protonEmail + " and may not work.")
+		}
+		options.ProtonEmail = &protonEmail
+		options.ProtonPassword = &protonPassword
+	}
+
 	options.SetDefaults(options.Providers[0])
 
 	err := options.Validate()
@@ -71,7 +88,11 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		return fmt.Errorf("options validation failed: %w", err)
 	}
 
-	storage, err := storage.New(logger, constants.ServersData)
+	serversDataPath := constants.ServersData
+	if maintainerMode {
+		serversDataPath = ""
+	}
+	storage, err := storage.New(logger, serversDataPath)
 	if err != nil {
 		return fmt.Errorf("creating servers storage: %w", err)
 	}
@@ -94,7 +115,7 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	openvpnFileExtractor := extract.New()
 
 	providers := provider.NewProviders(storage, time.Now, logger, httpClient,
-		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
+		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor, options)
 
 	updater := updater.New(httpClient, storage, providers, logger)
 	err = updater.UpdateServers(ctx, options.Providers, options.MinRatio)

internal/configuration/settings/deprecated.go

@@ -9,9 +9,11 @@ import (
 
 func readObsolete(r *reader.Reader) (warnings []string) {
 	keyToMessage := map[string]string{
-		"DOT_VERBOSITY":           "DOT_VERBOSITY is obsolete, use LOG_LEVEL instead.",
-		"DOT_VERBOSITY_DETAILS":   "DOT_VERBOSITY_DETAILS is obsolete because it was specific to Unbound.",
-		"DOT_VALIDATION_LOGLEVEL": "DOT_VALIDATION_LOGLEVEL is obsolete because DNSSEC validation is not implemented.",
+		"DOT_VERBOSITY":                "DOT_VERBOSITY is obsolete, use LOG_LEVEL instead.",
+		"DOT_VERBOSITY_DETAILS":        "DOT_VERBOSITY_DETAILS is obsolete because it was specific to Unbound.",
+		"DOT_VALIDATION_LOGLEVEL":      "DOT_VALIDATION_LOGLEVEL is obsolete because DNSSEC validation is not implemented.",
+		"HEALTH_VPN_DURATION_INITIAL":  "HEALTH_VPN_DURATION_INITIAL is obsolete",
+		"HEALTH_VPN_DURATION_ADDITION": "HEALTH_VPN_DURATION_ADDITION is obsolete",
 	}
 	sortedKeys := maps.Keys(keyToMessage)
 	slices.Sort(sortedKeys)

internal/configuration/settings/dns.go

@@ -1,9 +1,13 @@
 package settings
 
 import (
+	"errors"
 	"fmt"
 	"net/netip"
+	"time"
 
+	"github.com/qdm12/dns/v2/pkg/provider"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/reader"
 	"github.com/qdm12/gotree"
@@ -11,10 +15,31 @@ import (
 
 // DNS contains settings to configure DNS.
 type DNS struct {
+	// ServerEnabled is true if the server should be running
+	// and used. It defaults to true, and cannot be nil
+	// in the internal state.
+	ServerEnabled *bool
+	// UpstreamType can be dot or plain, and defaults to dot.
+	UpstreamType string `json:"upstream_type"`
+	// UpdatePeriod is the period to update DNS block lists.
+	// It can be set to 0 to disable the update.
+	// It defaults to 24h and cannot be nil in
+	// the internal state.
+	UpdatePeriod *time.Duration
+	// Providers is a list of DNS providers
+	Providers []string `json:"providers"`
+	// Caching is true if the server should cache
+	// DNS responses.
+	Caching *bool `json:"caching"`
+	// IPv6 is true if the server should connect over IPv6.
+	IPv6 *bool `json:"ipv6"`
+	// Blacklist contains settings to configure the filter
+	// block lists.
+	Blacklist DNSBlacklist
 	// ServerAddress is the DNS server to use inside
 	// the Go program and for the system.
 	// It defaults to '127.0.0.1' to be used with the
-	// DoT server. It cannot be the zero value in the internal
+	// local server. It cannot be the zero value in the internal
 	// state.
 	ServerAddress netip.Addr
 	// KeepNameserver is true if the existing DNS server
@@ -23,20 +48,40 @@ type DNS struct {
 	// outside the VPN tunnel since it would go through
 	// the local DNS server of your Docker/Kubernetes
 	// configuration, which is likely not going through the tunnel.
-	// This will also disable the DNS over TLS server and the
+	// This will also disable the DNS forwarder server and the
 	// `ServerAddress` field will be ignored.
 	// It defaults to false and cannot be nil in the
 	// internal state.
 	KeepNameserver *bool
-	// DOT contains settings to configure the DoT
-	// server.
-	DoT DoT
 }
 
+var (
+	ErrDNSUpstreamTypeNotValid = errors.New("DNS upstream type is not valid")
+	ErrDNSUpdatePeriodTooShort = errors.New("update period is too short")
+)
+
 func (d DNS) validate() (err error) {
-	err = d.DoT.validate()
+	if !helpers.IsOneOf(d.UpstreamType, "dot", "doh", "plain") {
+		return fmt.Errorf("%w: %s", ErrDNSUpstreamTypeNotValid, d.UpstreamType)
+	}
+
+	const minUpdatePeriod = 30 * time.Second
+	if *d.UpdatePeriod != 0 && *d.UpdatePeriod < minUpdatePeriod {
+		return fmt.Errorf("%w: %s must be bigger than %s",
+			ErrDNSUpdatePeriodTooShort, *d.UpdatePeriod, minUpdatePeriod)
+	}
+
+	providers := provider.NewProviders()
+	for _, providerName := range d.Providers {
+		_, err := providers.Get(providerName)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = d.Blacklist.validate()
 	if err != nil {
-		return fmt.Errorf("validating DoT settings: %w", err)
+		return err
 	}
 
 	return nil
@@ -44,9 +89,15 @@ func (d DNS) validate() (err error) {
 
 func (d *DNS) Copy() (copied DNS) {
 	return DNS{
+		ServerEnabled:  gosettings.CopyPointer(d.ServerEnabled),
+		UpstreamType:   d.UpstreamType,
+		UpdatePeriod:   gosettings.CopyPointer(d.UpdatePeriod),
+		Providers:      gosettings.CopySlice(d.Providers),
+		Caching:        gosettings.CopyPointer(d.Caching),
+		IPv6:           gosettings.CopyPointer(d.IPv6),
+		Blacklist:      d.Blacklist.copy(),
 		ServerAddress:  d.ServerAddress,
 		KeepNameserver: gosettings.CopyPointer(d.KeepNameserver),
-		DoT:            d.DoT.copy(),
 	}
 }
 
@@ -54,16 +105,48 @@ func (d *DNS) Copy() (copied DNS) {
 // settings object with any field set in the other
 // settings.
 func (d *DNS) overrideWith(other DNS) {
+	d.ServerEnabled = gosettings.OverrideWithPointer(d.ServerEnabled, other.ServerEnabled)
+	d.UpstreamType = gosettings.OverrideWithComparable(d.UpstreamType, other.UpstreamType)
+	d.UpdatePeriod = gosettings.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
+	d.Providers = gosettings.OverrideWithSlice(d.Providers, other.Providers)
+	d.Caching = gosettings.OverrideWithPointer(d.Caching, other.Caching)
+	d.IPv6 = gosettings.OverrideWithPointer(d.IPv6, other.IPv6)
+	d.Blacklist.overrideWith(other.Blacklist)
 	d.ServerAddress = gosettings.OverrideWithValidator(d.ServerAddress, other.ServerAddress)
 	d.KeepNameserver = gosettings.OverrideWithPointer(d.KeepNameserver, other.KeepNameserver)
-	d.DoT.overrideWith(other.DoT)
 }
 
 func (d *DNS) setDefaults() {
-	localhost := netip.AddrFrom4([4]byte{127, 0, 0, 1})
-	d.ServerAddress = gosettings.DefaultValidator(d.ServerAddress, localhost)
+	d.ServerEnabled = gosettings.DefaultPointer(d.ServerEnabled, true)
+	d.UpstreamType = gosettings.DefaultComparable(d.UpstreamType, "dot")
+	const defaultUpdatePeriod = 24 * time.Hour
+	d.UpdatePeriod = gosettings.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
+	d.Providers = gosettings.DefaultSlice(d.Providers, []string{
+		provider.Cloudflare().Name,
+	})
+	d.Caching = gosettings.DefaultPointer(d.Caching, true)
+	d.IPv6 = gosettings.DefaultPointer(d.IPv6, false)
+	d.Blacklist.setDefaults()
+	d.ServerAddress = gosettings.DefaultValidator(d.ServerAddress,
+		netip.AddrFrom4([4]byte{127, 0, 0, 1}))
 	d.KeepNameserver = gosettings.DefaultPointer(d.KeepNameserver, false)
-	d.DoT.setDefaults()
+}
+
+func (d DNS) GetFirstPlaintextIPv4() (ipv4 netip.Addr) {
+	localhost := netip.AddrFrom4([4]byte{127, 0, 0, 1})
+	if d.ServerAddress.Compare(localhost) != 0 && d.ServerAddress.Is4() {
+		return d.ServerAddress
+	}
+
+	providers := provider.NewProviders()
+	provider, err := providers.Get(d.Providers[0])
+	if err != nil {
+		// Settings should be validated before calling this function,
+		// so an error happening here is a programming error.
+		panic(err)
+	}
+
+	return provider.Plain.IPv4[0].Addr()
 }
 
 func (d DNS) String() string {
@@ -77,11 +160,63 @@ func (d DNS) toLinesNode() (node *gotree.Node) {
 		return node
 	}
 	node.Appendf("DNS server address to use: %s", d.ServerAddress)
-	node.AppendNode(d.DoT.toLinesNode())
+
+	node.Appendf("DNS forwarder server enabled: %s", gosettings.BoolToYesNo(d.ServerEnabled))
+	if !*d.ServerEnabled {
+		return node
+	}
+
+	node.Appendf("Upstream resolver type: %s", d.UpstreamType)
+
+	upstreamResolvers := node.Append("Upstream resolvers:")
+	for _, provider := range d.Providers {
+		upstreamResolvers.Append(provider)
+	}
+
+	node.Appendf("Caching: %s", gosettings.BoolToYesNo(d.Caching))
+	node.Appendf("IPv6: %s", gosettings.BoolToYesNo(d.IPv6))
+
+	update := "disabled"
+	if *d.UpdatePeriod > 0 {
+		update = "every " + d.UpdatePeriod.String()
+	}
+	node.Appendf("Update period: %s", update)
+
+	node.AppendNode(d.Blacklist.toLinesNode())
+
 	return node
 }
 
 func (d *DNS) read(r *reader.Reader) (err error) {
+	d.ServerEnabled, err = r.BoolPtr("DNS_SERVER", reader.RetroKeys("DOT"))
+	if err != nil {
+		return err
+	}
+
+	d.UpstreamType = r.String("DNS_UPSTREAM_RESOLVER_TYPE")
+
+	d.UpdatePeriod, err = r.DurationPtr("DNS_UPDATE_PERIOD")
+	if err != nil {
+		return err
+	}
+
+	d.Providers = r.CSV("DNS_UPSTREAM_RESOLVERS", reader.RetroKeys("DOT_PROVIDERS"))
+
+	d.Caching, err = r.BoolPtr("DNS_CACHING", reader.RetroKeys("DOT_CACHING"))
+	if err != nil {
+		return err
+	}
+
+	d.IPv6, err = r.BoolPtr("DNS_UPSTREAM_IPV6", reader.RetroKeys("DOT_IPV6"))
+	if err != nil {
+		return err
+	}
+
+	err = d.Blacklist.read(r)
+	if err != nil {
+		return err
+	}
+
 	d.ServerAddress, err = r.NetipAddr("DNS_ADDRESS", reader.RetroKeys("DNS_PLAINTEXT_ADDRESS"))
 	if err != nil {
 		return err
@@ -92,10 +227,5 @@ func (d *DNS) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	err = d.DoT.read(r)
-	if err != nil {
-		return fmt.Errorf("DNS over TLS settings: %w", err)
-	}
-
 	return nil
 }

internal/configuration/settings/dnsblacklist.go

@@ -22,6 +22,11 @@ type DNSBlacklist struct {
 	AddBlockedHosts      []string
 	AddBlockedIPs        []netip.Addr
 	AddBlockedIPPrefixes []netip.Prefix
+	// RebindingProtectionExemptHostnames is a list of hostnames
+	// exempt from DNS rebinding protection. It can contain parent
+	// domains which are of the form "*.example.com". Note the wildcard
+	// can only be used at the start of the hostname.
+	RebindingProtectionExemptHostnames []string
 }
 
 func (b *DNSBlacklist) setDefaults() {
@@ -33,8 +38,9 @@ func (b *DNSBlacklist) setDefaults() {
 var hostRegex = regexp.MustCompile(`^([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9_])(\.([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9]))*$`) //nolint:lll
 
 var (
-	ErrAllowedHostNotValid = errors.New("allowed host is not valid")
-	ErrBlockedHostNotValid = errors.New("blocked host is not valid")
+	ErrAllowedHostNotValid                   = errors.New("allowed host is not valid")
+	ErrBlockedHostNotValid                   = errors.New("blocked host is not valid")
+	ErrRebindingProtectionExemptHostNotValid = errors.New("rebinding protection exempt host is not valid")
 )
 
 func (b DNSBlacklist) validate() (err error) {
@@ -50,18 +56,28 @@ func (b DNSBlacklist) validate() (err error) {
 		}
 	}
 
+	for _, host := range b.RebindingProtectionExemptHostnames {
+		if len(host) > 2 && host[:2] == "*." {
+			host = host[2:]
+		}
+		if !hostRegex.MatchString(host) {
+			return fmt.Errorf("%w: %s", ErrRebindingProtectionExemptHostNotValid, host)
+		}
+	}
+
 	return nil
 }
 
 func (b DNSBlacklist) copy() (copied DNSBlacklist) {
 	return DNSBlacklist{
-		BlockMalicious:       gosettings.CopyPointer(b.BlockMalicious),
-		BlockAds:             gosettings.CopyPointer(b.BlockAds),
-		BlockSurveillance:    gosettings.CopyPointer(b.BlockSurveillance),
-		AllowedHosts:         gosettings.CopySlice(b.AllowedHosts),
-		AddBlockedHosts:      gosettings.CopySlice(b.AddBlockedHosts),
-		AddBlockedIPs:        gosettings.CopySlice(b.AddBlockedIPs),
-		AddBlockedIPPrefixes: gosettings.CopySlice(b.AddBlockedIPPrefixes),
+		BlockMalicious:                     gosettings.CopyPointer(b.BlockMalicious),
+		BlockAds:                           gosettings.CopyPointer(b.BlockAds),
+		BlockSurveillance:                  gosettings.CopyPointer(b.BlockSurveillance),
+		AllowedHosts:                       gosettings.CopySlice(b.AllowedHosts),
+		AddBlockedHosts:                    gosettings.CopySlice(b.AddBlockedHosts),
+		AddBlockedIPs:                      gosettings.CopySlice(b.AddBlockedIPs),
+		AddBlockedIPPrefixes:               gosettings.CopySlice(b.AddBlockedIPPrefixes),
+		RebindingProtectionExemptHostnames: gosettings.CopySlice(b.RebindingProtectionExemptHostnames),
 	}
 }
 
@@ -73,6 +89,8 @@ func (b *DNSBlacklist) overrideWith(other DNSBlacklist) {
 	b.AddBlockedHosts = gosettings.OverrideWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
 	b.AddBlockedIPs = gosettings.OverrideWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
 	b.AddBlockedIPPrefixes = gosettings.OverrideWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
+	b.RebindingProtectionExemptHostnames = gosettings.OverrideWithSlice(b.RebindingProtectionExemptHostnames,
+		other.RebindingProtectionExemptHostnames)
 }
 
 func (b DNSBlacklist) ToBlockBuilderSettings(client *http.Client) (
@@ -129,6 +147,13 @@ func (b DNSBlacklist) toLinesNode() (node *gotree.Node) {
 		}
 	}
 
+	if len(b.RebindingProtectionExemptHostnames) > 0 {
+		exemptHostsNode := node.Append("Rebinding protection exempt hostnames:")
+		for _, host := range b.RebindingProtectionExemptHostnames {
+			exemptHostsNode.Append(host)
+		}
+	}
+
 	return node
 }
 
@@ -149,23 +174,47 @@ func (b *DNSBlacklist) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	b.AddBlockedIPs, b.AddBlockedIPPrefixes,
-		err = readDoTPrivateAddresses(r) // TODO v4 split in 2
+	b.AddBlockedIPs, b.AddBlockedIPPrefixes, err = readDNSBlockedIPs(r)
 	if err != nil {
 		return err
 	}
 
-	b.AllowedHosts = r.CSV("UNBLOCK") // TODO v4 change name
+	b.AllowedHosts = r.CSV("DNS_UNBLOCK_HOSTNAMES", reader.RetroKeys("UNBLOCK"))
+
+	b.RebindingProtectionExemptHostnames = r.CSV("DNS_REBINDING_PROTECTION_EXEMPT_HOSTNAMES")
 
 	return nil
 }
 
-var ErrPrivateAddressNotValid = errors.New("private address is not a valid IP or CIDR range")
-
-func readDoTPrivateAddresses(reader *reader.Reader) (ips []netip.Addr,
+func readDNSBlockedIPs(r *reader.Reader) (ips []netip.Addr,
 	ipPrefixes []netip.Prefix, err error,
 ) {
-	privateAddresses := reader.CSV("DOT_PRIVATE_ADDRESS")
+	ips, err = r.CSVNetipAddresses("DNS_BLOCK_IPS")
+	if err != nil {
+		return nil, nil, err
+	}
+	ipPrefixes, err = r.CSVNetipPrefixes("DNS_BLOCK_IP_PREFIXES")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// TODO v4 remove this block below
+	privateIPs, privateIPPrefixes, err := readDNSPrivateAddresses(r)
+	if err != nil {
+		return nil, nil, err
+	}
+	ips = append(ips, privateIPs...)
+	ipPrefixes = append(ipPrefixes, privateIPPrefixes...)
+
+	return ips, ipPrefixes, nil
+}
+
+var ErrPrivateAddressNotValid = errors.New("private address is not a valid IP or CIDR range")
+
+func readDNSPrivateAddresses(r *reader.Reader) (ips []netip.Addr,
+	ipPrefixes []netip.Prefix, err error,
+) {
+	privateAddresses := r.CSV("DOT_PRIVATE_ADDRESS", reader.IsRetro("DNS_BLOCK_IP_PREFIXES"))
 	if len(privateAddresses) == 0 {
 		return nil, nil, nil
 	}

internal/configuration/settings/dot.go

@@ -1,170 +0,0 @@
-package settings
-
-import (
-	"errors"
-	"fmt"
-	"net/netip"
-	"time"
-
-	"github.com/qdm12/dns/v2/pkg/provider"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/reader"
-	"github.com/qdm12/gotree"
-)
-
-// DoT contains settings to configure the DoT server.
-type DoT struct {
-	// Enabled is true if the DoT server should be running
-	// and used. It defaults to true, and cannot be nil
-	// in the internal state.
-	Enabled *bool
-	// UpdatePeriod is the period to update DNS block lists.
-	// It can be set to 0 to disable the update.
-	// It defaults to 24h and cannot be nil in
-	// the internal state.
-	UpdatePeriod *time.Duration
-	// Providers is a list of DNS over TLS providers
-	Providers []string `json:"providers"`
-	// Caching is true if the DoT server should cache
-	// DNS responses.
-	Caching *bool `json:"caching"`
-	// IPv6 is true if the DoT server should connect over IPv6.
-	IPv6 *bool `json:"ipv6"`
-	// Blacklist contains settings to configure the filter
-	// block lists.
-	Blacklist DNSBlacklist
-}
-
-var ErrDoTUpdatePeriodTooShort = errors.New("update period is too short")
-
-func (d DoT) validate() (err error) {
-	const minUpdatePeriod = 30 * time.Second
-	if *d.UpdatePeriod != 0 && *d.UpdatePeriod < minUpdatePeriod {
-		return fmt.Errorf("%w: %s must be bigger than %s",
-			ErrDoTUpdatePeriodTooShort, *d.UpdatePeriod, minUpdatePeriod)
-	}
-
-	providers := provider.NewProviders()
-	for _, providerName := range d.Providers {
-		_, err := providers.Get(providerName)
-		if err != nil {
-			return err
-		}
-	}
-
-	err = d.Blacklist.validate()
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (d *DoT) copy() (copied DoT) {
-	return DoT{
-		Enabled:      gosettings.CopyPointer(d.Enabled),
-		UpdatePeriod: gosettings.CopyPointer(d.UpdatePeriod),
-		Providers:    gosettings.CopySlice(d.Providers),
-		Caching:      gosettings.CopyPointer(d.Caching),
-		IPv6:         gosettings.CopyPointer(d.IPv6),
-		Blacklist:    d.Blacklist.copy(),
-	}
-}
-
-// overrideWith overrides fields of the receiver
-// settings object with any field set in the other
-// settings.
-func (d *DoT) overrideWith(other DoT) {
-	d.Enabled = gosettings.OverrideWithPointer(d.Enabled, other.Enabled)
-	d.UpdatePeriod = gosettings.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
-	d.Providers = gosettings.OverrideWithSlice(d.Providers, other.Providers)
-	d.Caching = gosettings.OverrideWithPointer(d.Caching, other.Caching)
-	d.IPv6 = gosettings.OverrideWithPointer(d.IPv6, other.IPv6)
-	d.Blacklist.overrideWith(other.Blacklist)
-}
-
-func (d *DoT) setDefaults() {
-	d.Enabled = gosettings.DefaultPointer(d.Enabled, true)
-	const defaultUpdatePeriod = 24 * time.Hour
-	d.UpdatePeriod = gosettings.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
-	d.Providers = gosettings.DefaultSlice(d.Providers, []string{
-		provider.Cloudflare().Name,
-	})
-	d.Caching = gosettings.DefaultPointer(d.Caching, true)
-	d.IPv6 = gosettings.DefaultPointer(d.IPv6, false)
-	d.Blacklist.setDefaults()
-}
-
-func (d DoT) GetFirstPlaintextIPv4() (ipv4 netip.Addr) {
-	providers := provider.NewProviders()
-	provider, err := providers.Get(d.Providers[0])
-	if err != nil {
-		// Settings should be validated before calling this function,
-		// so an error happening here is a programming error.
-		panic(err)
-	}
-
-	return provider.DoT.IPv4[0].Addr()
-}
-
-func (d DoT) String() string {
-	return d.toLinesNode().String()
-}
-
-func (d DoT) toLinesNode() (node *gotree.Node) {
-	node = gotree.New("DNS over TLS settings:")
-
-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(d.Enabled))
-	if !*d.Enabled {
-		return node
-	}
-
-	update := "disabled" //nolint:goconst
-	if *d.UpdatePeriod > 0 {
-		update = "every " + d.UpdatePeriod.String()
-	}
-	node.Appendf("Update period: %s", update)
-
-	upstreamResolvers := node.Append("Upstream resolvers:")
-	for _, provider := range d.Providers {
-		upstreamResolvers.Append(provider)
-	}
-
-	node.Appendf("Caching: %s", gosettings.BoolToYesNo(d.Caching))
-	node.Appendf("IPv6: %s", gosettings.BoolToYesNo(d.IPv6))
-
-	node.AppendNode(d.Blacklist.toLinesNode())
-
-	return node
-}
-
-func (d *DoT) read(reader *reader.Reader) (err error) {
-	d.Enabled, err = reader.BoolPtr("DOT")
-	if err != nil {
-		return err
-	}
-
-	d.UpdatePeriod, err = reader.DurationPtr("DNS_UPDATE_PERIOD")
-	if err != nil {
-		return err
-	}
-
-	d.Providers = reader.CSV("DOT_PROVIDERS")
-
-	d.Caching, err = reader.BoolPtr("DOT_CACHING")
-	if err != nil {
-		return err
-	}
-
-	d.IPv6, err = reader.BoolPtr("DOT_IPV6")
-	if err != nil {
-		return err
-	}
-
-	err = d.Blacklist.read(reader)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}

internal/configuration/settings/errors.go

@@ -36,6 +36,8 @@ var (
 	ErrSystemPUIDNotValid              = errors.New("process user id is not valid")
 	ErrSystemTimezoneNotValid          = errors.New("timezone is not valid")
 	ErrUpdaterPeriodTooSmall           = errors.New("VPN server data updater period is too small")
+	ErrUpdaterProtonPasswordMissing    = errors.New("proton password is missing")
+	ErrUpdaterProtonEmailMissing       = errors.New("proton email is missing")
 	ErrVPNProviderNameNotValid         = errors.New("VPN provider name is not valid")
 	ErrVPNTypeNotValid                 = errors.New("VPN type is not valid")
 	ErrWireguardAllowedIPNotSet        = errors.New("allowed IP is not set")

internal/configuration/settings/health.go

@@ -1,9 +1,10 @@
 package settings
 
 import (
+	"errors"
 	"fmt"
+	"net/netip"
 	"os"
-	"time"
 
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/reader"
@@ -17,34 +18,51 @@ type Health struct {
 	// for the health check server.
 	// It cannot be the empty string in the internal state.
 	ServerAddress string
-	// ReadHeaderTimeout is the HTTP server header read timeout
-	// duration of the HTTP server. It defaults to 100 milliseconds.
-	ReadHeaderTimeout time.Duration
-	// ReadTimeout is the HTTP read timeout duration of the
-	// HTTP server. It defaults to 500 milliseconds.
-	ReadTimeout time.Duration
-	// TargetAddress is the address (host or host:port)
-	// to TCP dial to periodically for the health check.
-	// It cannot be the empty string in the internal state.
-	TargetAddress string
-	// SuccessWait is the duration to wait to re-run the
-	// healthcheck after a successful healthcheck.
-	// It defaults to 5 seconds and cannot be zero in
-	// the internal state.
-	SuccessWait time.Duration
-	// VPN has health settings specific to the VPN loop.
-	VPN HealthyWait
+	// TargetAddresses are the addresses (host or host:port)
+	// to TCP TLS dial to periodically for the health check.
+	// Addresses after the first one are used as fallbacks for retries.
+	// It cannot be empty in the internal state.
+	TargetAddresses []string
+	// ICMPTargetIPs are the IP addresses to use for ICMP echo requests
+	// in the health checker. The slice can be set to a single
+	// unspecified address (0.0.0.0) such that the VPN server IP is used,
+	// although this can be less reliable. It defaults to [1.1.1.1,8.8.8.8],
+	// and cannot be left empty in the internal state.
+	ICMPTargetIPs []netip.Addr
+	// SmallCheckType is the type of small health check to perform.
+	// It can be "icmp" or "dns", and defaults to "icmp".
+	// Note it changes automatically to dns if icmp is not supported.
+	SmallCheckType string
+	// RestartVPN indicates whether to restart the VPN connection
+	// when the healthcheck fails.
+	RestartVPN *bool
 }
 
+var (
+	ErrICMPTargetIPNotValid       = errors.New("ICMP target IP address is not valid")
+	ErrICMPTargetIPsNotCompatible = errors.New("ICMP target IP addresses are not compatible")
+	ErrSmallCheckTypeNotValid     = errors.New("small check type is not valid")
+)
+
 func (h Health) Validate() (err error) {
 	err = validate.ListeningAddress(h.ServerAddress, os.Getuid())
 	if err != nil {
 		return fmt.Errorf("server listening address is not valid: %w", err)
 	}
 
-	err = h.VPN.validate()
+	for _, ip := range h.ICMPTargetIPs {
+		switch {
+		case !ip.IsValid():
+			return fmt.Errorf("%w: %s", ErrICMPTargetIPNotValid, ip)
+		case ip.IsUnspecified() && len(h.ICMPTargetIPs) > 1:
+			return fmt.Errorf("%w: only a single IP address must be set if it is to be unspecified",
+				ErrICMPTargetIPsNotCompatible)
+		}
+	}
+
+	err = validate.IsOneOf(h.SmallCheckType, "icmp", "dns")
 	if err != nil {
-		return fmt.Errorf("health VPN settings: %w", err)
+		return fmt.Errorf("%w: %s", ErrSmallCheckTypeNotValid, err)
 	}
 
 	return nil
@@ -52,12 +70,11 @@ func (h Health) Validate() (err error) {
 
 func (h *Health) copy() (copied Health) {
 	return Health{
-		ServerAddress:     h.ServerAddress,
-		ReadHeaderTimeout: h.ReadHeaderTimeout,
-		ReadTimeout:       h.ReadTimeout,
-		TargetAddress:     h.TargetAddress,
-		SuccessWait:       h.SuccessWait,
-		VPN:               h.VPN.copy(),
+		ServerAddress:   h.ServerAddress,
+		TargetAddresses: h.TargetAddresses,
+		ICMPTargetIPs:   gosettings.CopySlice(h.ICMPTargetIPs),
+		SmallCheckType:  h.SmallCheckType,
+		RestartVPN:      gosettings.CopyPointer(h.RestartVPN),
 	}
 }
 
@@ -66,23 +83,21 @@ func (h *Health) copy() (copied Health) {
 // settings.
 func (h *Health) OverrideWith(other Health) {
 	h.ServerAddress = gosettings.OverrideWithComparable(h.ServerAddress, other.ServerAddress)
-	h.ReadHeaderTimeout = gosettings.OverrideWithComparable(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = gosettings.OverrideWithComparable(h.ReadTimeout, other.ReadTimeout)
-	h.TargetAddress = gosettings.OverrideWithComparable(h.TargetAddress, other.TargetAddress)
-	h.SuccessWait = gosettings.OverrideWithComparable(h.SuccessWait, other.SuccessWait)
-	h.VPN.overrideWith(other.VPN)
+	h.TargetAddresses = gosettings.OverrideWithSlice(h.TargetAddresses, other.TargetAddresses)
+	h.ICMPTargetIPs = gosettings.OverrideWithSlice(h.ICMPTargetIPs, other.ICMPTargetIPs)
+	h.SmallCheckType = gosettings.OverrideWithComparable(h.SmallCheckType, other.SmallCheckType)
+	h.RestartVPN = gosettings.OverrideWithPointer(h.RestartVPN, other.RestartVPN)
 }
 
 func (h *Health) SetDefaults() {
 	h.ServerAddress = gosettings.DefaultComparable(h.ServerAddress, "127.0.0.1:9999")
-	const defaultReadHeaderTimeout = 100 * time.Millisecond
-	h.ReadHeaderTimeout = gosettings.DefaultComparable(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
-	const defaultReadTimeout = 500 * time.Millisecond
-	h.ReadTimeout = gosettings.DefaultComparable(h.ReadTimeout, defaultReadTimeout)
-	h.TargetAddress = gosettings.DefaultComparable(h.TargetAddress, "cloudflare.com:443")
-	const defaultSuccessWait = 5 * time.Second
-	h.SuccessWait = gosettings.DefaultComparable(h.SuccessWait, defaultSuccessWait)
-	h.VPN.setDefaults()
+	h.TargetAddresses = gosettings.DefaultSlice(h.TargetAddresses, []string{"cloudflare.com:443", "github.com:443"})
+	h.ICMPTargetIPs = gosettings.DefaultSlice(h.ICMPTargetIPs, []netip.Addr{
+		netip.AddrFrom4([4]byte{1, 1, 1, 1}),
+		netip.AddrFrom4([4]byte{8, 8, 8, 8}),
+	})
+	h.SmallCheckType = gosettings.DefaultComparable(h.SmallCheckType, "icmp")
+	h.RestartVPN = gosettings.DefaultPointer(h.RestartVPN, true)
 }
 
 func (h Health) String() string {
@@ -92,28 +107,40 @@ func (h Health) String() string {
 func (h Health) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Health settings:")
 	node.Appendf("Server listening address: %s", h.ServerAddress)
-	node.Appendf("Target address: %s", h.TargetAddress)
-	node.Appendf("Duration to wait after success: %s", h.SuccessWait)
-	node.Appendf("Read header timeout: %s", h.ReadHeaderTimeout)
-	node.Appendf("Read timeout: %s", h.ReadTimeout)
-	node.AppendNode(h.VPN.toLinesNode("VPN"))
+	targetAddrs := node.Appendf("Target addresses:")
+	for _, targetAddr := range h.TargetAddresses {
+		targetAddrs.Append(targetAddr)
+	}
+	switch h.SmallCheckType {
+	case "icmp":
+		icmpNode := node.Appendf("Small health check type: ICMP echo request")
+		if len(h.ICMPTargetIPs) == 1 && h.ICMPTargetIPs[0].IsUnspecified() {
+			icmpNode.Appendf("ICMP target IP: VPN server IP address")
+		} else {
+			icmpIPs := icmpNode.Appendf("ICMP target IPs:")
+			for _, ip := range h.ICMPTargetIPs {
+				icmpIPs.Append(ip.String())
+			}
+		}
+	case "dns":
+		node.Appendf("Small health check type: Plain DNS lookup over UDP")
+	}
+	node.Appendf("Restart VPN on healthcheck failure: %s", gosettings.BoolToYesNo(h.RestartVPN))
 	return node
 }
 
 func (h *Health) Read(r *reader.Reader) (err error) {
 	h.ServerAddress = r.String("HEALTH_SERVER_ADDRESS")
-	h.TargetAddress = r.String("HEALTH_TARGET_ADDRESS",
-		reader.RetroKeys("HEALTH_ADDRESS_TO_PING"))
-
-	h.SuccessWait, err = r.Duration("HEALTH_SUCCESS_WAIT_DURATION")
+	h.TargetAddresses = r.CSV("HEALTH_TARGET_ADDRESSES",
+		reader.RetroKeys("HEALTH_ADDRESS_TO_PING", "HEALTH_TARGET_ADDRESS"))
+	h.ICMPTargetIPs, err = r.CSVNetipAddresses("HEALTH_ICMP_TARGET_IPS", reader.RetroKeys("HEALTH_ICMP_TARGET_IP"))
 	if err != nil {
 		return err
 	}
-
-	err = h.VPN.read(r)
+	h.SmallCheckType = r.String("HEALTH_SMALL_CHECK_TYPE")
+	h.RestartVPN, err = r.BoolPtr("HEALTH_RESTART_VPN")
 	if err != nil {
-		return fmt.Errorf("VPN health settings: %w", err)
+		return err
 	}
-
 	return nil
 }

internal/configuration/settings/healthywait.go

@@ -1,76 +0,0 @@
-package settings
-
-import (
-	"time"
-
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/reader"
-	"github.com/qdm12/gotree"
-)
-
-type HealthyWait struct {
-	// Initial is the initial duration to wait for the program
-	// to be healthy before taking action.
-	// It cannot be nil in the internal state.
-	Initial *time.Duration
-	// Addition is the duration to add to the Initial duration
-	// after Initial has expired to wait longer for the program
-	// to be healthy.
-	// It cannot be nil in the internal state.
-	Addition *time.Duration
-}
-
-func (h HealthyWait) validate() (err error) {
-	return nil
-}
-
-func (h *HealthyWait) copy() (copied HealthyWait) {
-	return HealthyWait{
-		Initial:  gosettings.CopyPointer(h.Initial),
-		Addition: gosettings.CopyPointer(h.Addition),
-	}
-}
-
-// overrideWith overrides fields of the receiver
-// settings object with any field set in the other
-// settings.
-func (h *HealthyWait) overrideWith(other HealthyWait) {
-	h.Initial = gosettings.OverrideWithPointer(h.Initial, other.Initial)
-	h.Addition = gosettings.OverrideWithPointer(h.Addition, other.Addition)
-}
-
-func (h *HealthyWait) setDefaults() {
-	const initialDurationDefault = 6 * time.Second
-	const additionDurationDefault = 5 * time.Second
-	h.Initial = gosettings.DefaultPointer(h.Initial, initialDurationDefault)
-	h.Addition = gosettings.DefaultPointer(h.Addition, additionDurationDefault)
-}
-
-func (h HealthyWait) String() string {
-	return h.toLinesNode("Health").String()
-}
-
-func (h HealthyWait) toLinesNode(kind string) (node *gotree.Node) {
-	node = gotree.New(kind + " wait durations:")
-	node.Appendf("Initial duration: %s", *h.Initial)
-	node.Appendf("Additional duration: %s", *h.Addition)
-	return node
-}
-
-func (h *HealthyWait) read(r *reader.Reader) (err error) {
-	h.Initial, err = r.DurationPtr(
-		"HEALTH_VPN_DURATION_INITIAL",
-		reader.RetroKeys("HEALTH_OPENVPN_DURATION_INITIAL"))
-	if err != nil {
-		return err
-	}
-
-	h.Addition, err = r.DurationPtr(
-		"HEALTH_VPN_DURATION_ADDITION",
-		reader.RetroKeys("HEALTH_OPENVPN_DURATION_ADDITION"))
-	if err != nil {
-		return err
-	}
-
-	return nil
-}

internal/configuration/settings/openvpn.go

@@ -209,8 +209,7 @@ func validateOpenVPNClientKey(vpnProvider, clientKey string) (err error) {
 	case
 		providers.Airvpn,
 		providers.Cyberghost,
-		providers.VPNUnlimited,
-		providers.Wevpn:
+		providers.VPNUnlimited:
 		if clientKey == "" {
 			return fmt.Errorf("%w", ErrMissingValue)
 		}

internal/configuration/settings/openvpnselection.go

@@ -2,6 +2,7 @@ package settings
 
 import (
 	"fmt"
+	"net/netip"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
@@ -24,6 +25,12 @@ type OpenVPNSelection struct {
 	// and can be udp or tcp. It cannot be the empty string
 	// in the internal state.
 	Protocol string `json:"protocol"`
+	// EndpointIP is the server endpoint IP address.
+	// If set, it overrides any IP address from the picked
+	// built-in server connection. To indicate it should
+	// not be used, it should be set to [netip.IPv4Unspecified].
+	// It can never be the zero value in the internal state.
+	EndpointIP netip.Addr `json:"endpoint_ip"`
 	// CustomPort is the OpenVPN server endpoint port.
 	// It can be set to 0 to indicate no custom port should
 	// be used. It cannot be nil in the internal state.
@@ -97,13 +104,10 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 				allowedUDP = []uint16{53, 1194, 1197, 1198, 8080, 9201}
 			case providers.Protonvpn:
 				allowedTCP = []uint16{443, 5995, 8443}
-				allowedUDP = []uint16{80, 443, 1194, 4569, 5060}
+				allowedUDP = []uint16{80, 443, 1194, 4569, 5060, 51820}
 			case providers.SlickVPN:
 				allowedTCP = []uint16{443, 8080, 8888}
 				allowedUDP = []uint16{443, 8080, 8888}
-			case providers.Wevpn:
-				allowedTCP = []uint16{53, 1195, 1199, 2018}
-				allowedUDP = []uint16{80, 1194, 1198}
 			case providers.Windscribe:
 				allowedTCP = []uint16{21, 22, 80, 123, 143, 443, 587, 1194, 3306, 8080, 54783}
 				allowedUDP = []uint16{53, 80, 123, 443, 1194, 54783}
@@ -142,6 +146,7 @@ func (o *OpenVPNSelection) copy() (copied OpenVPNSelection) {
 	return OpenVPNSelection{
 		ConfFile:     gosettings.CopyPointer(o.ConfFile),
 		Protocol:     o.Protocol,
+		EndpointIP:   o.EndpointIP,
 		CustomPort:   gosettings.CopyPointer(o.CustomPort),
 		PIAEncPreset: gosettings.CopyPointer(o.PIAEncPreset),
 	}
@@ -151,12 +156,14 @@ func (o *OpenVPNSelection) overrideWith(other OpenVPNSelection) {
 	o.ConfFile = gosettings.OverrideWithPointer(o.ConfFile, other.ConfFile)
 	o.Protocol = gosettings.OverrideWithComparable(o.Protocol, other.Protocol)
 	o.CustomPort = gosettings.OverrideWithPointer(o.CustomPort, other.CustomPort)
+	o.EndpointIP = gosettings.OverrideWithValidator(o.EndpointIP, other.EndpointIP)
 	o.PIAEncPreset = gosettings.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
 }
 
 func (o *OpenVPNSelection) setDefaults(vpnProvider string) {
 	o.ConfFile = gosettings.DefaultPointer(o.ConfFile, "")
 	o.Protocol = gosettings.DefaultComparable(o.Protocol, constants.UDP)
+	o.EndpointIP = gosettings.DefaultValidator(o.EndpointIP, netip.IPv4Unspecified())
 	o.CustomPort = gosettings.DefaultPointer(o.CustomPort, 0)
 
 	var defaultEncPreset string
@@ -174,6 +181,10 @@ func (o OpenVPNSelection) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("OpenVPN server selection settings:")
 	node.Appendf("Protocol: %s", strings.ToUpper(o.Protocol))
 
+	if !o.EndpointIP.IsUnspecified() {
+		node.Appendf("Endpoint IP address: %s", o.EndpointIP)
+	}
+
 	if *o.CustomPort != 0 {
 		node.Appendf("Custom port: %d", *o.CustomPort)
 	}
@@ -194,6 +205,12 @@ func (o *OpenVPNSelection) read(r *reader.Reader) (err error) {
 
 	o.Protocol = r.String("OPENVPN_PROTOCOL", reader.RetroKeys("PROTOCOL"))
 
+	o.EndpointIP, err = r.NetipAddr("OPENVPN_ENDPOINT_IP",
+		reader.RetroKeys("OPENVPN_TARGET_IP", "VPN_ENDPOINT_IP"))
+	if err != nil {
+		return err
+	}
+
 	o.CustomPort, err = r.Uint16Ptr("OPENVPN_ENDPOINT_PORT",
 		reader.RetroKeys("PORT", "OPENVPN_PORT", "VPN_ENDPOINT_PORT"))
 	if err != nil {

internal/configuration/settings/pmtud.go

@@ -0,0 +1,111 @@
+package settings
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+
+	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gosettings/reader"
+	"github.com/qdm12/gotree"
+)
+
+// PMTUD contains settings to configure Path MTU Discovery.
+type PMTUD struct {
+	// ICMPAddresses is the redundancy list of addresses to use
+	// for ICMP path MTU discovery. Each address MUST handle ICMP
+	// packets for PMTUD to work.
+	// It cannot be nil in the internal state.
+	ICMPAddresses []netip.Addr `json:"icmp_addresses"`
+	// TCPAddresses is the redundancy list of addresses to use
+	// for TCP path MTU discovery. Each address MUST have a listening
+	// TCP server on the port specified.
+	// It cannot be nil in the internal state.
+	TCPAddresses []netip.AddrPort `json:"tcp_addresses"`
+}
+
+var (
+	ErrPMTUDICMPAddressNotValid = errors.New("PMTUD ICMP address is not valid")
+	ErrPMTUDTCPAddressNotValid  = errors.New("PMTUD TCP address is not valid")
+)
+
+// Validate validates PMTUD settings.
+func (p PMTUD) validate() (err error) {
+	for i, addr := range p.ICMPAddresses {
+		if !addr.IsValid() {
+			return fmt.Errorf("%w: at index %d", ErrPMTUDICMPAddressNotValid, i)
+		}
+	}
+	for i, addr := range p.TCPAddresses {
+		if !addr.IsValid() {
+			return fmt.Errorf("%w: at index %d", ErrPMTUDTCPAddressNotValid, i)
+		}
+	}
+	return nil
+}
+
+func (p *PMTUD) copy() (copied PMTUD) {
+	return PMTUD{
+		ICMPAddresses: gosettings.CopySlice(p.ICMPAddresses),
+		TCPAddresses:  gosettings.CopySlice(p.TCPAddresses),
+	}
+}
+
+func (p *PMTUD) overrideWith(other PMTUD) {
+	p.ICMPAddresses = gosettings.OverrideWithSlice(p.ICMPAddresses, other.ICMPAddresses)
+	p.TCPAddresses = gosettings.OverrideWithSlice(p.TCPAddresses, other.TCPAddresses)
+}
+
+func (p *PMTUD) setDefaults() {
+	defaultICMPAddresses := []netip.Addr{
+		netip.AddrFrom4([4]byte{1, 1, 1, 1}),
+		netip.AddrFrom4([4]byte{8, 8, 8, 8}),
+	}
+	p.ICMPAddresses = gosettings.DefaultSlice(p.ICMPAddresses, defaultICMPAddresses)
+
+	const dnsPort, tlsPort = 53, 443
+	defaultTCPAddresses := []netip.AddrPort{
+		netip.AddrPortFrom(netip.AddrFrom4([4]byte{1, 1, 1, 1}), dnsPort),
+		netip.AddrPortFrom(netip.AddrFrom4([4]byte{8, 8, 8, 8}), dnsPort),
+		netip.AddrPortFrom(netip.AddrFrom4([4]byte{1, 1, 1, 1}), tlsPort),
+		netip.AddrPortFrom(netip.AddrFrom4([4]byte{8, 8, 8, 8}), tlsPort),
+		netip.AddrPortFrom(netip.MustParseAddr("2606:4700:4700::1111"), dnsPort),
+		netip.AddrPortFrom(netip.MustParseAddr("2001:4860:4860::8888"), dnsPort),
+		netip.AddrPortFrom(netip.MustParseAddr("2606:4700:4700::1111"), tlsPort),
+		netip.AddrPortFrom(netip.MustParseAddr("2001:4860:4860::8888"), tlsPort),
+	}
+	p.TCPAddresses = gosettings.DefaultSlice(p.TCPAddresses, defaultTCPAddresses)
+}
+
+func (p PMTUD) String() string {
+	return p.toLinesNode().String()
+}
+
+func (p PMTUD) toLinesNode() (node *gotree.Node) {
+	node = gotree.New("Path MTU discovery:")
+
+	icmpAddrNode := node.Append("ICMP addresses:")
+	for _, addr := range p.ICMPAddresses {
+		icmpAddrNode.Append(addr.String())
+	}
+
+	tcpAddrNode := node.Append("TCP addresses:")
+	for _, addr := range p.TCPAddresses {
+		tcpAddrNode.Append(addr.String())
+	}
+	return node
+}
+
+func (p *PMTUD) read(r *reader.Reader) (err error) {
+	p.ICMPAddresses, err = r.CSVNetipAddresses("PMTUD_ICMP_ADDRESSES")
+	if err != nil {
+		return err
+	}
+
+	p.TCPAddresses, err = r.CSVNetipAddrPorts("PMTUD_TCP_ADDRESSES")
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

internal/configuration/settings/provider.go

@@ -2,6 +2,8 @@ package settings
 
 import (
 	"fmt"
+	"slices"
+	"sort"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/constants/providers"
@@ -31,6 +33,11 @@ func (p *Provider) validate(vpnType string, filterChoicesGetter FilterChoicesGet
 	if vpnType == vpn.OpenVPN {
 		validNames = providers.AllWithCustom()
 		validNames = append(validNames, "pia") // Retro-compatibility
+		// Remove Mullvad since it no longer supports OpenVPN as of January 15th, 2026
+		mullvadIndex := slices.Index(validNames, providers.Mullvad)
+		validNames[mullvadIndex], validNames[len(validNames)-1] = validNames[len(validNames)-1], validNames[mullvadIndex]
+		validNames = validNames[:len(validNames)-1]
+		sort.Strings(validNames)
 	} else { // Wireguard
 		validNames = []string{
 			providers.Airvpn,

internal/configuration/settings/server.go

@@ -1,11 +1,14 @@
 package settings
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"net"
 	"os"
 	"strconv"
 
+	"github.com/qdm12/gluetun/internal/server/middlewares/auth"
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/reader"
 	"github.com/qdm12/gotree"
@@ -24,6 +27,9 @@ type ControlServer struct {
 	// It cannot be empty in the internal state and defaults to
 	// /gluetun/auth/config.toml.
 	AuthFilePath string
+	// AuthDefaultRole is a JSON encoded object defining the default role
+	// that applies to all routes without a previously user-defined role assigned to.
+	AuthDefaultRole string
 }
 
 func (c ControlServer) validate() (err error) {
@@ -44,14 +50,30 @@ func (c ControlServer) validate() (err error) {
 			ErrControlServerPrivilegedPort, port, uid)
 	}
 
+	jsonDecoder := json.NewDecoder(bytes.NewBufferString(c.AuthDefaultRole))
+	jsonDecoder.DisallowUnknownFields()
+	var role auth.Role
+	err = jsonDecoder.Decode(&role)
+	if err != nil {
+		return fmt.Errorf("default authentication role is not valid JSON: %w", err)
+	}
+
+	if role.Auth != "" {
+		err = role.Validate()
+		if err != nil {
+			return fmt.Errorf("default authentication role is not valid: %w", err)
+		}
+	}
+
 	return nil
 }
 
 func (c *ControlServer) copy() (copied ControlServer) {
 	return ControlServer{
-		Address:      gosettings.CopyPointer(c.Address),
-		Log:          gosettings.CopyPointer(c.Log),
-		AuthFilePath: c.AuthFilePath,
+		Address:         gosettings.CopyPointer(c.Address),
+		Log:             gosettings.CopyPointer(c.Log),
+		AuthFilePath:    c.AuthFilePath,
+		AuthDefaultRole: c.AuthDefaultRole,
 	}
 }
 
@@ -62,12 +84,21 @@ func (c *ControlServer) overrideWith(other ControlServer) {
 	c.Address = gosettings.OverrideWithPointer(c.Address, other.Address)
 	c.Log = gosettings.OverrideWithPointer(c.Log, other.Log)
 	c.AuthFilePath = gosettings.OverrideWithComparable(c.AuthFilePath, other.AuthFilePath)
+	c.AuthDefaultRole = gosettings.OverrideWithComparable(c.AuthDefaultRole, other.AuthDefaultRole)
 }
 
 func (c *ControlServer) setDefaults() {
 	c.Address = gosettings.DefaultPointer(c.Address, ":8000")
 	c.Log = gosettings.DefaultPointer(c.Log, true)
 	c.AuthFilePath = gosettings.DefaultComparable(c.AuthFilePath, "/gluetun/auth/config.toml")
+	c.AuthDefaultRole = gosettings.DefaultComparable(c.AuthDefaultRole, "{}")
+	if c.AuthDefaultRole != "{}" {
+		var role auth.Role
+		_ = json.Unmarshal([]byte(c.AuthDefaultRole), &role)
+		role.Name = "default"
+		roleBytes, _ := json.Marshal(role) //nolint:errchkjson
+		c.AuthDefaultRole = string(roleBytes)
+	}
 }
 
 func (c ControlServer) String() string {
@@ -79,6 +110,11 @@ func (c ControlServer) toLinesNode() (node *gotree.Node) {
 	node.Appendf("Listening address: %s", *c.Address)
 	node.Appendf("Logging: %s", gosettings.BoolToYesNo(c.Log))
 	node.Appendf("Authentication file path: %s", c.AuthFilePath)
+	if c.AuthDefaultRole != "{}" {
+		var role auth.Role
+		_ = json.Unmarshal([]byte(c.AuthDefaultRole), &role)
+		node.AppendNode(role.ToLinesNode())
+	}
 	return node
 }
 
@@ -91,6 +127,7 @@ func (c *ControlServer) read(r *reader.Reader) (err error) {
 	c.Address = r.Get("HTTP_CONTROL_SERVER_ADDRESS")
 
 	c.AuthFilePath = r.String("HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH")
+	c.AuthDefaultRole = r.String("HTTP_CONTROL_SERVER_AUTH_DEFAULT_ROLE", reader.ForceLowercase(false))
 
 	return nil
 }

internal/configuration/settings/serverselection.go

@@ -3,7 +3,6 @@ package settings
 import (
 	"errors"
 	"fmt"
-	"net/netip"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
@@ -17,17 +16,11 @@ import (
 	"github.com/qdm12/gotree"
 )
 
-type ServerSelection struct { //nolint:maligned
+type ServerSelection struct {
 	// VPN is the VPN type which can be 'openvpn'
 	// or 'wireguard'. It cannot be the empty string
 	// in the internal state.
 	VPN string `json:"vpn"`
-	// TargetIP is the server endpoint IP address to use.
-	// It will override any IP address from the picked
-	// built-in server. It cannot be the empty value in the internal
-	// state, and can be set to the unspecified address to indicate
-	// there is not target IP address to use.
-	TargetIP netip.Addr `json:"target_ip"`
 	// Countries is the list of countries to filter VPN servers with.
 	Countries []string `json:"countries"`
 	// Categories is the list of categories to filter VPN servers with.
@@ -299,7 +292,6 @@ func validateFeatureFilters(settings ServerSelection, vpnServiceProvider string)
 func (ss *ServerSelection) copy() (copied ServerSelection) {
 	return ServerSelection{
 		VPN:             ss.VPN,
-		TargetIP:        ss.TargetIP,
 		Countries:       gosettings.CopySlice(ss.Countries),
 		Categories:      gosettings.CopySlice(ss.Categories),
 		Regions:         gosettings.CopySlice(ss.Regions),
@@ -323,7 +315,6 @@ func (ss *ServerSelection) copy() (copied ServerSelection) {
 
 func (ss *ServerSelection) overrideWith(other ServerSelection) {
 	ss.VPN = gosettings.OverrideWithComparable(ss.VPN, other.VPN)
-	ss.TargetIP = gosettings.OverrideWithValidator(ss.TargetIP, other.TargetIP)
 	ss.Countries = gosettings.OverrideWithSlice(ss.Countries, other.Countries)
 	ss.Categories = gosettings.OverrideWithSlice(ss.Categories, other.Categories)
 	ss.Regions = gosettings.OverrideWithSlice(ss.Regions, other.Regions)
@@ -346,7 +337,6 @@ func (ss *ServerSelection) overrideWith(other ServerSelection) {
 
 func (ss *ServerSelection) setDefaults(vpnProvider string, portForwardingEnabled bool) {
 	ss.VPN = gosettings.DefaultComparable(ss.VPN, vpn.OpenVPN)
-	ss.TargetIP = gosettings.DefaultValidator(ss.TargetIP, netip.IPv4Unspecified())
 	ss.OwnedOnly = gosettings.DefaultPointer(ss.OwnedOnly, false)
 	ss.FreeOnly = gosettings.DefaultPointer(ss.FreeOnly, false)
 	ss.PremiumOnly = gosettings.DefaultPointer(ss.PremiumOnly, false)
@@ -354,11 +344,8 @@ func (ss *ServerSelection) setDefaults(vpnProvider string, portForwardingEnabled
 	ss.SecureCoreOnly = gosettings.DefaultPointer(ss.SecureCoreOnly, false)
 	ss.TorOnly = gosettings.DefaultPointer(ss.TorOnly, false)
 	ss.MultiHopOnly = gosettings.DefaultPointer(ss.MultiHopOnly, false)
-	defaultPortForwardOnly := false
-	if portForwardingEnabled && helpers.IsOneOf(vpnProvider,
-		providers.PrivateInternetAccess, providers.Protonvpn) {
-		defaultPortForwardOnly = true
-	}
+	defaultPortForwardOnly := portForwardingEnabled &&
+		helpers.IsOneOf(vpnProvider, providers.PrivateInternetAccess, providers.Protonvpn)
 	ss.PortForwardOnly = gosettings.DefaultPointer(ss.PortForwardOnly, defaultPortForwardOnly)
 	ss.OpenVPN.setDefaults(vpnProvider)
 	ss.Wireguard.setDefaults()
@@ -371,9 +358,6 @@ func (ss ServerSelection) String() string {
 func (ss ServerSelection) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Server selection settings:")
 	node.Appendf("VPN type: %s", ss.VPN)
-	if !ss.TargetIP.IsUnspecified() {
-		node.Appendf("Target IP address: %s", ss.TargetIP)
-	}
 
 	if len(ss.Countries) > 0 {
 		node.Appendf("Countries: %s", strings.Join(ss.Countries, ", "))
@@ -464,12 +448,6 @@ func (ss *ServerSelection) read(r *reader.Reader,
 ) (err error) {
 	ss.VPN = vpnType
 
-	ss.TargetIP, err = r.NetipAddr("OPENVPN_ENDPOINT_IP",
-		reader.RetroKeys("OPENVPN_TARGET_IP", "VPN_ENDPOINT_IP"))
-	if err != nil {
-		return err
-	}
-
 	countriesRetroKeys := []string{"COUNTRY"}
 	if vpnProvider == providers.Cyberghost {
 		countriesRetroKeys = append(countriesRetroKeys, "REGION")

internal/configuration/settings/settings.go

@@ -177,10 +177,10 @@ func (s Settings) Warnings() (warnings []string) {
 	// TODO remove in v4
 	if s.DNS.ServerAddress.Unmap().Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
 		warnings = append(warnings, "DNS address is set to "+s.DNS.ServerAddress.String()+
-			" so the DNS over TLS (DoT) server will not be used."+
-			" The default value changed to 127.0.0.1 so it uses the internal DoT serves."+
-			" If the DoT server fails to start, the IPv4 address of the first plaintext DNS server"+
-			" corresponding to the first DoT provider chosen is used.")
+			" so the local forwarding DNS server will not be used."+
+			" The default value changed to 127.0.0.1 so it uses the internal DNS server."+
+			" If this server fails to start, the IPv4 address of the first plaintext DNS server"+
+			" corresponding to the first DNS provider chosen is used.")
 	}
 
 	return warnings

internal/configuration/settings/settings_test.go

@@ -29,41 +29,55 @@ func Test_Settings_String(t *testing.T) {
 |   |       └── OpenVPN server selection settings:
 |   |           ├── Protocol: UDP
 |   |           └── Private Internet Access encryption preset: strong
-|   └── OpenVPN settings:
-|       ├── OpenVPN version: 2.6
-|       ├── User: [not set]
-|       ├── Password: [not set]
-|       ├── Private Internet Access encryption preset: strong
-|       ├── Network interface: tun0
-|       ├── Run OpenVPN as: root
-|       └── Verbosity level: 1
+|   ├── OpenVPN settings:
+|   |   ├── OpenVPN version: 2.6
+|   |   ├── User: [not set]
+|   |   ├── Password: [not set]
+|   |   ├── Private Internet Access encryption preset: strong
+|   |   ├── Network interface: tun0
+|   |   ├── Run OpenVPN as: root
+|   |   └── Verbosity level: 1
+|   └── Path MTU discovery:
+|       ├── ICMP addresses:
+|       |   ├── 1.1.1.1
+|       |   └── 8.8.8.8
+|       └── TCP addresses:
+|           ├── 1.1.1.1:53
+|           ├── 8.8.8.8:53
+|           ├── 1.1.1.1:443
+|           ├── 8.8.8.8:443
+|           ├── [2606:4700:4700::1111]:53
+|           ├── [2001:4860:4860::8888]:53
+|           ├── [2606:4700:4700::1111]:443
+|           └── [2001:4860:4860::8888]:443
 ├── DNS settings:
 |   ├── Keep existing nameserver(s): no
 |   ├── DNS server address to use: 127.0.0.1
-|   └── DNS over TLS settings:
-|       ├── Enabled: yes
-|       ├── Update period: every 24h0m0s
-|       ├── Upstream resolvers:
-|       |   └── Cloudflare
-|       ├── Caching: yes
-|       ├── IPv6: no
-|       └── DNS filtering settings:
-|           ├── Block malicious: yes
-|           ├── Block ads: no
-|           └── Block surveillance: yes
+|   ├── DNS forwarder server enabled: yes
+|   ├── Upstream resolver type: dot
+|   ├── Upstream resolvers:
+|   |   └── Cloudflare
+|   ├── Caching: yes
+|   ├── IPv6: no
+|   ├── Update period: every 24h0m0s
+|   └── DNS filtering settings:
+|       ├── Block malicious: yes
+|       ├── Block ads: no
+|       └── Block surveillance: yes
 ├── Firewall settings:
 |   └── Enabled: yes
 ├── Log settings:
 |   └── Log level: INFO
 ├── Health settings:
 |   ├── Server listening address: 127.0.0.1:9999
-|   ├── Target address: cloudflare.com:443
-|   ├── Duration to wait after success: 5s
-|   ├── Read header timeout: 100ms
-|   ├── Read timeout: 500ms
-|   └── VPN wait durations:
-|       ├── Initial duration: 6s
-|       └── Additional duration: 5s
+|   ├── Target addresses:
+|   |   ├── cloudflare.com:443
+|   |   └── github.com:443
+|   ├── Small health check type: ICMP echo request
+|   |   └── ICMP target IPs:
+|   |       ├── 1.1.1.1
+|   |       └── 8.8.8.8
+|   └── Restart VPN on healthcheck failure: yes
 ├── Shadowsocks server settings:
 |   └── Enabled: no
 ├── HTTP proxy settings:

internal/configuration/settings/shadowsocks.go

@@ -15,7 +15,7 @@ type Shadowsocks struct {
 	// It defaults to false, and cannot be nil in the internal state.
 	Enabled *bool
 	// Settings are settings for the TCP+UDP server.
-	tcpudp.Settings
+	Settings tcpudp.Settings
 }
 
 func (s Shadowsocks) validate() (err error) {

internal/configuration/settings/updater.go

@@ -2,6 +2,7 @@ package settings
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -31,6 +32,10 @@ type Updater struct {
 	// Providers is the list of VPN service providers
 	// to update server information for.
 	Providers []string
+	// ProtonEmail is the email to authenticate with the Proton API.
+	ProtonEmail *string
+	// ProtonPassword is the password to authenticate with the Proton API.
+	ProtonPassword *string
 }
 
 func (u Updater) Validate() (err error) {
@@ -51,6 +56,18 @@ func (u Updater) Validate() (err error) {
 		if err != nil {
 			return fmt.Errorf("%w: %w", ErrVPNProviderNameNotValid, err)
 		}
+
+		if provider == providers.Protonvpn {
+			authenticatedAPI := *u.ProtonEmail != "" || *u.ProtonPassword != ""
+			if authenticatedAPI {
+				switch {
+				case *u.ProtonEmail == "":
+					return fmt.Errorf("%w", ErrUpdaterProtonEmailMissing)
+				case *u.ProtonPassword == "":
+					return fmt.Errorf("%w", ErrUpdaterProtonPasswordMissing)
+				}
+			}
+		}
 	}
 
 	return nil
@@ -58,10 +75,12 @@ func (u Updater) Validate() (err error) {
 
 func (u *Updater) copy() (copied Updater) {
 	return Updater{
-		Period:     gosettings.CopyPointer(u.Period),
-		DNSAddress: u.DNSAddress,
-		MinRatio:   u.MinRatio,
-		Providers:  gosettings.CopySlice(u.Providers),
+		Period:         gosettings.CopyPointer(u.Period),
+		DNSAddress:     u.DNSAddress,
+		MinRatio:       u.MinRatio,
+		Providers:      gosettings.CopySlice(u.Providers),
+		ProtonEmail:    gosettings.CopyPointer(u.ProtonEmail),
+		ProtonPassword: gosettings.CopyPointer(u.ProtonPassword),
 	}
 }
 
@@ -73,6 +92,8 @@ func (u *Updater) overrideWith(other Updater) {
 	u.DNSAddress = gosettings.OverrideWithComparable(u.DNSAddress, other.DNSAddress)
 	u.MinRatio = gosettings.OverrideWithComparable(u.MinRatio, other.MinRatio)
 	u.Providers = gosettings.OverrideWithSlice(u.Providers, other.Providers)
+	u.ProtonEmail = gosettings.OverrideWithPointer(u.ProtonEmail, other.ProtonEmail)
+	u.ProtonPassword = gosettings.OverrideWithPointer(u.ProtonPassword, other.ProtonPassword)
 }
 
 func (u *Updater) SetDefaults(vpnProvider string) {
@@ -87,6 +108,10 @@ func (u *Updater) SetDefaults(vpnProvider string) {
 	if len(u.Providers) == 0 && vpnProvider != providers.Custom {
 		u.Providers = []string{vpnProvider}
 	}
+
+	// Set these to empty strings to avoid nil pointer panics
+	u.ProtonEmail = gosettings.DefaultPointer(u.ProtonEmail, "")
+	u.ProtonPassword = gosettings.DefaultPointer(u.ProtonPassword, "")
 }
 
 func (u Updater) String() string {
@@ -103,6 +128,10 @@ func (u Updater) toLinesNode() (node *gotree.Node) {
 	node.Appendf("DNS address: %s", u.DNSAddress)
 	node.Appendf("Minimum ratio: %.1f", u.MinRatio)
 	node.Appendf("Providers to update: %s", strings.Join(u.Providers, ", "))
+	if slices.Contains(u.Providers, providers.Protonvpn) {
+		node.Appendf("Proton API email: %s", *u.ProtonEmail)
+		node.Appendf("Proton API password: %s", gosettings.ObfuscateKey(*u.ProtonPassword))
+	}
 
 	return node
 }
@@ -125,6 +154,16 @@ func (u *Updater) read(r *reader.Reader) (err error) {
 
 	u.Providers = r.CSV("UPDATER_VPN_SERVICE_PROVIDERS")
 
+	u.ProtonEmail = r.Get("UPDATER_PROTONVPN_EMAIL")
+	if u.ProtonEmail == nil {
+		protonUsername := r.String("UPDATER_PROTONVPN_USERNAME", reader.IsRetro("UPDATER_PROTONVPN_EMAIL"))
+		if protonUsername != "" {
+			protonEmail := protonUsername + "@protonmail.com"
+			u.ProtonEmail = &protonEmail
+		}
+	}
+	u.ProtonPassword = r.Get("UPDATER_PROTONVPN_PASSWORD")
+
 	return nil
 }
 

internal/configuration/settings/vpn.go

@@ -18,6 +18,7 @@ type VPN struct {
 	Provider  Provider  `json:"provider"`
 	OpenVPN   OpenVPN   `json:"openvpn"`
 	Wireguard Wireguard `json:"wireguard"`
+	PMTUD     PMTUD     `json:"pmtud"`
 }
 
 // TODO v4 remove pointer for receiver (because of Surfshark).
@@ -45,6 +46,11 @@ func (v *VPN) Validate(filterChoicesGetter FilterChoicesGetter, ipv6Supported bo
 		}
 	}
 
+	err = v.PMTUD.validate()
+	if err != nil {
+		return fmt.Errorf("PMTUD settings: %w", err)
+	}
+
 	return nil
 }
 
@@ -54,6 +60,7 @@ func (v *VPN) Copy() (copied VPN) {
 		Provider:  v.Provider.copy(),
 		OpenVPN:   v.OpenVPN.copy(),
 		Wireguard: v.Wireguard.copy(),
+		PMTUD:     v.PMTUD.copy(),
 	}
 }
 
@@ -62,6 +69,7 @@ func (v *VPN) OverrideWith(other VPN) {
 	v.Provider.overrideWith(other.Provider)
 	v.OpenVPN.overrideWith(other.OpenVPN)
 	v.Wireguard.overrideWith(other.Wireguard)
+	v.PMTUD.overrideWith(other.PMTUD)
 }
 
 func (v *VPN) setDefaults() {
@@ -69,6 +77,7 @@ func (v *VPN) setDefaults() {
 	v.Provider.setDefaults()
 	v.OpenVPN.setDefaults(v.Provider.Name)
 	v.Wireguard.setDefaults(v.Provider.Name)
+	v.PMTUD.setDefaults()
 }
 
 func (v VPN) String() string {
@@ -85,6 +94,7 @@ func (v VPN) toLinesNode() (node *gotree.Node) {
 	} else {
 		node.AppendNode(v.Wireguard.toLinesNode())
 	}
+	node.AppendNode(v.PMTUD.toLinesNode())
 
 	return node
 }
@@ -107,5 +117,10 @@ func (v *VPN) read(r *reader.Reader) (err error) {
 		return fmt.Errorf("wireguard: %w", err)
 	}
 
+	err = v.PMTUD.read(r)
+	if err != nil {
+		return fmt.Errorf("PMTUD: %w", err)
+	}
+
 	return nil
 }

internal/configuration/settings/wireguard.go

@@ -38,14 +38,9 @@ type Wireguard struct {
 	Interface                   string         `json:"interface"`
 	PersistentKeepaliveInterval *time.Duration `json:"persistent_keep_alive_interval"`
 	// Maximum Transmission Unit (MTU) of the Wireguard interface.
-	// It cannot be zero in the internal state, and defaults to
-	// 1320. Note it is not the wireguard-go MTU default of 1420
-	// because this impacts bandwidth a lot on some VPN providers,
-	// see https://github.com/qdm12/gluetun/issues/1650.
-	// It has been lowered to 1320 following quite a bit of
-	// investigation in the issue:
-	// https://github.com/qdm12/gluetun/issues/2533.
-	MTU uint16 `json:"mtu"`
+	// It cannot be nil in the internal state, and defaults to
+	// 0 indicating to use PMTUD.
+	MTU *uint32 `json:"mtu"`
 	// Implementation is the Wireguard implementation to use.
 	// It can be "auto", "userspace" or "kernelspace".
 	// It defaults to "auto" and cannot be the empty string
@@ -194,8 +189,7 @@ func (w *Wireguard) setDefaults(vpnProvider string) {
 	w.AllowedIPs = gosettings.DefaultSlice(w.AllowedIPs, defaultAllowedIPs)
 	w.PersistentKeepaliveInterval = gosettings.DefaultPointer(w.PersistentKeepaliveInterval, 0)
 	w.Interface = gosettings.DefaultComparable(w.Interface, "wg0")
-	const defaultMTU = 1320
-	w.MTU = gosettings.DefaultComparable(w.MTU, defaultMTU)
+	w.MTU = gosettings.DefaultPointer(w.MTU, 0)
 	w.Implementation = gosettings.DefaultComparable(w.Implementation, "auto")
 }
 
@@ -231,7 +225,11 @@ func (w Wireguard) toLinesNode() (node *gotree.Node) {
 	}
 
 	interfaceNode := node.Appendf("Network interface: %s", w.Interface)
-	interfaceNode.Appendf("MTU: %d", w.MTU)
+	if *w.MTU == 0 {
+		interfaceNode.Append("MTU: use path MTU discovery")
+	} else {
+		interfaceNode.Appendf("MTU: %d", *w.MTU)
+	}
 
 	if w.Implementation != "auto" {
 		node.Appendf("Implementation: %s", w.Implementation)
@@ -272,11 +270,9 @@ func (w *Wireguard) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	mtuPtr, err := r.Uint16Ptr("WIREGUARD_MTU")
+	w.MTU, err = r.Uint32Ptr("WIREGUARD_MTU")
 	if err != nil {
 		return err
-	} else if mtuPtr != nil {
-		w.MTU = *mtuPtr
 	}
 	return nil
 }

internal/configuration/settings/wireguardselection.go

@@ -14,11 +14,11 @@ import (
 
 type WireguardSelection struct {
 	// EndpointIP is the server endpoint IP address.
-	// It is only used with VPN providers generating Wireguard
-	// configurations specific to each server and user.
-	// To indicate it should not be used, it should be set
-	// to netip.IPv4Unspecified(). It can never be the zero value
-	// in the internal state.
+	// It is notably required with the custom provider.
+	// Otherwise it overrides any IP address from the picked
+	// built-in server connection. To indicate it should
+	// not be used, it should be set to [netip.IPv4Unspecified].
+	// It can never be the zero value in the internal state.
 	EndpointIP netip.Addr `json:"endpoint_ip"`
 	// EndpointPort is a the server port to use for the VPN server.
 	// It is optional for VPN providers IVPN, Mullvad, Surfshark
@@ -155,7 +155,8 @@ func (w WireguardSelection) toLinesNode() (node *gotree.Node) {
 func (w *WireguardSelection) read(r *reader.Reader) (err error) {
 	w.EndpointIP, err = r.NetipAddr("WIREGUARD_ENDPOINT_IP", reader.RetroKeys("VPN_ENDPOINT_IP"))
 	if err != nil {
-		return err
+		return fmt.Errorf("%w - note this MUST be an IP address, "+
+			"see https://github.com/qdm12/gluetun/issues/788", err)
 	}
 
 	w.EndpointPort, err = r.Uint16Ptr("WIREGUARD_ENDPOINT_PORT", reader.RetroKeys("VPN_ENDPOINT_PORT"))

internal/constants/providers/providers.go

@@ -27,7 +27,6 @@ const (
 	VPNSecure             = "vpnsecure"
 	VPNUnlimited          = "vpn unlimited"
 	Vyprvpn               = "vyprvpn"
-	Wevpn                 = "wevpn"
 	Windscribe            = "windscribe"
 )
 
@@ -56,7 +55,6 @@ func All() []string {
 		VPNSecure,
 		VPNUnlimited,
 		Vyprvpn,
-		Wevpn,
 		Windscribe,
 	}
 }

internal/dns/loop.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"net/netip"
 	"time"
 
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/mapfilter"
@@ -16,22 +17,23 @@ import (
 )
 
 type Loop struct {
-	statusManager *loopstate.State
-	state         *state.State
-	server        *server.Server
-	filter        *mapfilter.Filter
-	resolvConf    string
-	client        *http.Client
-	logger        Logger
-	userTrigger   bool
-	start         <-chan struct{}
-	running       chan<- models.LoopStatus
-	stop          <-chan struct{}
-	stopped       chan<- struct{}
-	updateTicker  <-chan struct{}
-	backoffTime   time.Duration
-	timeNow       func() time.Time
-	timeSince     func(time.Time) time.Duration
+	statusManager  *loopstate.State
+	state          *state.State
+	server         *server.Server
+	filter         *mapfilter.Filter
+	localResolvers []netip.Addr
+	resolvConf     string
+	client         *http.Client
+	logger         Logger
+	userTrigger    bool
+	start          <-chan struct{}
+	running        chan<- models.LoopStatus
+	stop           <-chan struct{}
+	stopped        chan<- struct{}
+	updateTicker   <-chan struct{}
+	backoffTime    time.Duration
+	timeNow        func() time.Time
+	timeSince      func(time.Time) time.Duration
 }
 
 const defaultBackoffTime = 10 * time.Second
@@ -48,7 +50,9 @@ func NewLoop(settings settings.DNS,
 	statusManager := loopstate.New(constants.Stopped, start, running, stop, stopped)
 	state := state.New(statusManager, settings, updateTicker)
 
-	filter, err := mapfilter.New(mapfilter.Settings{})
+	filter, err := mapfilter.New(mapfilter.Settings{
+		Logger: buildFilterLogger(logger),
+	})
 	if err != nil {
 		return nil, fmt.Errorf("creating map filter: %w", err)
 	}
@@ -100,3 +104,15 @@ func (l *Loop) signalOrSetStatus(status models.LoopStatus) {
 		l.statusManager.SetStatus(status)
 	}
 }
+
+type filterLogger struct {
+	logger Logger
+}
+
+func (l *filterLogger) Log(msg string) {
+	l.logger.Debug(msg)
+}
+
+func buildFilterLogger(logger Logger) *filterLogger {
+	return &filterLogger{logger: logger}
+}

internal/dns/plaintext.go

@@ -10,15 +10,7 @@ import (
 func (l *Loop) useUnencryptedDNS(fallback bool) {
 	settings := l.GetSettings()
 
-	// Try with user provided plaintext ip address
-	// if it's not 127.0.0.1 (default for DoT), otherwise
-	// use the first DoT provider ipv4 address found.
-	var targetIP netip.Addr
-	if settings.ServerAddress.Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
-		targetIP = settings.ServerAddress
-	} else {
-		targetIP = settings.DoT.GetFirstPlaintextIPv4()
-	}
+	targetIP := settings.GetFirstPlaintextIPv4()
 
 	if fallback {
 		l.logger.Info("falling back on plaintext DNS at address " + targetIP.String())
@@ -27,14 +19,15 @@ func (l *Loop) useUnencryptedDNS(fallback bool) {
 	}
 
 	const dialTimeout = 3 * time.Second
+	const defaultDNSPort = 53
 	settingsInternalDNS := nameserver.SettingsInternalDNS{
-		IP:      targetIP,
-		Timeout: dialTimeout,
+		AddrPort: netip.AddrPortFrom(targetIP, defaultDNSPort),
+		Timeout:  dialTimeout,
 	}
 	nameserver.UseDNSInternally(settingsInternalDNS)
 
 	settingsSystemWide := nameserver.SettingsSystemDNS{
-		IP:         targetIP,
+		IPs:        []netip.Addr{targetIP},
 		ResolvPath: l.resolvConf,
 	}
 	err := nameserver.UseDNSSystemWide(settingsSystemWide)

internal/dns/run.go

@@ -2,14 +2,21 @@ package dns
 
 import (
 	"context"
-	"errors"
 
+	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/gluetun/internal/constants"
 )
 
 func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 	defer close(done)
 
+	var err error
+	l.localResolvers, err = nameserver.GetPrivateDNSServers()
+	if err != nil {
+		l.logger.Error("getting private DNS servers: " + err.Error())
+		return
+	}
+
 	if *l.GetSettings().KeepNameserver {
 		l.logger.Warn("⚠️⚠️⚠️  keeping the default container nameservers, " +
 			"this will likely leak DNS traffic outside the VPN " +
@@ -26,18 +33,22 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 	}
 
 	for ctx.Err() == nil {
-		// Upper scope variables for the DNS over TLS server only
+		// Upper scope variables for the DNS forwarder server only
 		// Their values are to be used if DOT=off
 		var runError <-chan error
 
 		settings := l.GetSettings()
-		for !*settings.KeepNameserver && *settings.DoT.Enabled {
+		for !*settings.KeepNameserver && *settings.ServerEnabled {
 			var err error
 			runError, err = l.setupServer(ctx)
 			if err == nil {
 				l.backoffTime = defaultBackoffTime
-				l.logger.Info("ready")
-				l.signalOrSetStatus(constants.Running)
+				l.logger.Info("ready and using DNS server at address " + settings.ServerAddress.String())
+
+				err = l.updateFiles(ctx, settings)
+				if err != nil {
+					l.logger.Warn("downloading block lists failed, skipping: " + err.Error())
+				}
 				break
 			}
 
@@ -46,17 +57,13 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			if ctx.Err() != nil {
 				return
 			}
-
-			if !errors.Is(err, errUpdateBlockLists) {
-				const fallback = true
-				l.useUnencryptedDNS(fallback)
-			}
 			l.logAndWait(ctx, err)
 			settings = l.GetSettings()
 		}
+		l.signalOrSetStatus(constants.Running)
 
 		settings = l.GetSettings()
-		if !*settings.KeepNameserver && !*settings.DoT.Enabled {
+		if !*settings.KeepNameserver && !*settings.ServerEnabled {
 			const fallback = false
 			l.useUnencryptedDNS(fallback)
 		}
@@ -74,15 +81,21 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 	for {
 		select {
 		case <-ctx.Done():
-			l.stopServer()
-			// TODO revert OS and Go nameserver when exiting
+			settings := l.GetSettings()
+			if !*settings.KeepNameserver && *settings.ServerEnabled {
+				l.stopServer()
+				// TODO revert OS and Go nameserver when exiting
+			}
 			return true
 		case <-l.stop:
 			l.userTrigger = true
 			l.logger.Info("stopping")
-			const fallback = false
-			l.useUnencryptedDNS(fallback)
-			l.stopServer()
+			settings := l.GetSettings()
+			if !*settings.KeepNameserver && *settings.ServerEnabled {
+				const fallback = false
+				l.useUnencryptedDNS(fallback)
+				l.stopServer()
+			}
 			l.stopped <- struct{}{}
 		case <-l.start:
 			l.userTrigger = true
@@ -101,6 +114,6 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 func (l *Loop) stopServer() {
 	stopErr := l.server.Stop()
 	if stopErr != nil {
-		l.logger.Error("stopping DoT server: " + stopErr.Error())
+		l.logger.Error("stopping server: " + stopErr.Error())
 	}
 }

internal/dns/settings.go

@@ -3,12 +3,16 @@ package dns
 import (
 	"context"
 	"fmt"
+	"net/netip"
 
+	"github.com/qdm12/dns/v2/pkg/doh"
 	"github.com/qdm12/dns/v2/pkg/dot"
 	cachemiddleware "github.com/qdm12/dns/v2/pkg/middlewares/cache"
 	"github.com/qdm12/dns/v2/pkg/middlewares/cache/lru"
 	filtermiddleware "github.com/qdm12/dns/v2/pkg/middlewares/filter"
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/mapfilter"
+	"github.com/qdm12/dns/v2/pkg/middlewares/localdns"
+	"github.com/qdm12/dns/v2/pkg/plain"
 	"github.com/qdm12/dns/v2/pkg/provider"
 	"github.com/qdm12/dns/v2/pkg/server"
 	"github.com/qdm12/gluetun/internal/configuration/settings"
@@ -22,33 +26,63 @@ func (l *Loop) SetSettings(ctx context.Context, settings settings.DNS) (
 	return l.state.SetSettings(ctx, settings)
 }
 
-func buildDoTSettings(settings settings.DNS,
-	filter *mapfilter.Filter, logger Logger) (
+func buildServerSettings(settings settings.DNS,
+	filter *mapfilter.Filter, localResolvers []netip.Addr,
+	logger Logger) (
 	serverSettings server.Settings, err error,
 ) {
 	serverSettings.Logger = logger
 
-	var dotSettings dot.Settings
 	providersData := provider.NewProviders()
-	dotSettings.UpstreamResolvers = make([]provider.Provider, len(settings.DoT.Providers))
-	for i := range settings.DoT.Providers {
+	upstreamResolvers := make([]provider.Provider, len(settings.Providers))
+	for i := range settings.Providers {
 		var err error
-		dotSettings.UpstreamResolvers[i], err = providersData.Get(settings.DoT.Providers[i])
+		upstreamResolvers[i], err = providersData.Get(settings.Providers[i])
 		if err != nil {
 			panic(err) // this should already had been checked
 		}
 	}
-	dotSettings.IPVersion = "ipv4"
-	if *settings.DoT.IPv6 {
-		dotSettings.IPVersion = "ipv6"
+
+	ipVersion := "ipv4"
+	if *settings.IPv6 {
+		ipVersion = "ipv6"
 	}
 
-	serverSettings.Dialer, err = dot.New(dotSettings)
-	if err != nil {
-		return server.Settings{}, fmt.Errorf("creating DNS over TLS dialer: %w", err)
+	var dialer server.Dialer
+	switch settings.UpstreamType {
+	case "dot":
+		dialerSettings := dot.Settings{
+			UpstreamResolvers: upstreamResolvers,
+			IPVersion:         ipVersion,
+		}
+		dialer, err = dot.New(dialerSettings)
+		if err != nil {
+			return server.Settings{}, fmt.Errorf("creating DNS over TLS dialer: %w", err)
+		}
+	case "doh":
+		dialerSettings := doh.Settings{
+			UpstreamResolvers: upstreamResolvers,
+			IPVersion:         ipVersion,
+		}
+		dialer, err = doh.New(dialerSettings)
+		if err != nil {
+			return server.Settings{}, fmt.Errorf("creating DNS over HTTPS dialer: %w", err)
+		}
+	case "plain":
+		dialerSettings := plain.Settings{
+			UpstreamResolvers: upstreamResolvers,
+			IPVersion:         ipVersion,
+		}
+		dialer, err = plain.New(dialerSettings)
+		if err != nil {
+			return server.Settings{}, fmt.Errorf("creating plain DNS dialer: %w", err)
+		}
+	default:
+		panic("unknown upstream type: " + settings.UpstreamType)
 	}
+	serverSettings.Dialer = dialer
 
-	if *settings.DoT.Caching {
+	if *settings.Caching {
 		lruCache, err := lru.New(lru.Settings{})
 		if err != nil {
 			return server.Settings{}, fmt.Errorf("creating LRU cache: %w", err)
@@ -70,5 +104,22 @@ func buildDoTSettings(settings settings.DNS,
 	}
 	serverSettings.Middlewares = append(serverSettings.Middlewares, filterMiddleware)
 
+	localResolversAddrPorts := make([]netip.AddrPort, len(localResolvers))
+	const defaultDNSPort = 53
+	for i, addr := range localResolvers {
+		localResolversAddrPorts[i] = netip.AddrPortFrom(addr, defaultDNSPort)
+	}
+	localDNSMiddleware, err := localdns.New(localdns.Settings{
+		Resolvers: localResolversAddrPorts, // auto-detected at container start only
+		Logger:    logger,
+	})
+	if err != nil {
+		return server.Settings{}, fmt.Errorf("creating local DNS middleware: %w", err)
+	}
+	// Place after cache middleware, since we want to avoid caching for local
+	// hostnames that may change regularly.
+	// Place after filter middleware to avoid conflicts with the rebinding protection.
+	serverSettings.Middlewares = append(serverSettings.Middlewares, localDNSMiddleware)
+
 	return serverSettings, nil
 }

internal/dns/setup.go

@@ -2,32 +2,32 @@ package dns
 
 import (
 	"context"
-	"errors"
 	"fmt"
+	"net/netip"
 
 	"github.com/qdm12/dns/v2/pkg/check"
+	"github.com/qdm12/dns/v2/pkg/middlewares/filter/update"
 	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/dns/v2/pkg/server"
 )
 
-var errUpdateBlockLists = errors.New("cannot update filter block lists")
-
 func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err error) {
-	err = l.updateFiles(ctx)
-	if err != nil {
-		return nil, fmt.Errorf("%w: %w", errUpdateBlockLists, err)
-	}
-
 	settings := l.GetSettings()
-
-	dotSettings, err := buildDoTSettings(settings, l.filter, l.logger)
+	var updateSettings update.Settings
+	updateSettings.SetRebindingProtectionExempt(settings.Blacklist.RebindingProtectionExemptHostnames)
+	err = l.filter.Update(updateSettings)
 	if err != nil {
-		return nil, fmt.Errorf("building DoT settings: %w", err)
+		return nil, fmt.Errorf("updating filter for rebinding protection: %w", err)
 	}
 
-	server, err := server.New(dotSettings)
+	serverSettings, err := buildServerSettings(settings, l.filter, l.localResolvers, l.logger)
 	if err != nil {
-		return nil, fmt.Errorf("creating DoT server: %w", err)
+		return nil, fmt.Errorf("building server settings: %w", err)
+	}
+
+	server, err := server.New(serverSettings)
+	if err != nil {
+		return nil, fmt.Errorf("creating server: %w", err)
 	}
 
 	runError, err = server.Start(ctx)
@@ -37,11 +37,12 @@ func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err erro
 	l.server = server
 
 	// use internal DNS server
+	const defaultDNSPort = 53
 	nameserver.UseDNSInternally(nameserver.SettingsInternalDNS{
-		IP: settings.ServerAddress,
+		AddrPort: netip.AddrPortFrom(settings.ServerAddress, defaultDNSPort),
 	})
 	err = nameserver.UseDNSSystemWide(nameserver.SettingsSystemDNS{
-		IP:         settings.ServerAddress,
+		IPs:        []netip.Addr{settings.ServerAddress},
 		ResolvPath: l.resolvConf,
 	})
 	if err != nil {

internal/dns/state/settings.go

@@ -27,7 +27,7 @@ func (s *State) SetSettings(ctx context.Context, settings settings.DNS) (
 
 	// Check for only update period change
 	tempSettings := s.settings.Copy()
-	*tempSettings.DoT.UpdatePeriod = *settings.DoT.UpdatePeriod
+	*tempSettings.UpdatePeriod = *settings.UpdatePeriod
 	onlyUpdatePeriodChanged := reflect.DeepEqual(tempSettings, settings)
 
 	s.settings = settings
@@ -40,7 +40,7 @@ func (s *State) SetSettings(ctx context.Context, settings settings.DNS) (
 
 	// Restart
 	_, _ = s.statusApplier.ApplyStatus(ctx, constants.Stopped)
-	if *settings.DoT.Enabled {
+	if *settings.ServerEnabled {
 		outcome, _ = s.statusApplier.ApplyStatus(ctx, constants.Running)
 	}
 	return outcome

internal/dns/ticker.go

@@ -14,7 +14,7 @@ func (l *Loop) RunRestartTicker(ctx context.Context, done chan<- struct{}) {
 	timer.Stop()
 	timerIsStopped := true
 	settings := l.GetSettings()
-	if period := *settings.DoT.UpdatePeriod; period > 0 {
+	if period := *settings.UpdatePeriod; period > 0 {
 		timer.Reset(period)
 		timerIsStopped = false
 	}
@@ -28,29 +28,20 @@ func (l *Loop) RunRestartTicker(ctx context.Context, done chan<- struct{}) {
 			return
 		case <-timer.C:
 			lastTick = l.timeNow()
-
-			status := l.GetStatus()
-			if status == constants.Running {
-				if err := l.updateFiles(ctx); err != nil {
-					l.statusManager.SetStatus(constants.Crashed)
-					l.logger.Error(err.Error())
-					l.logger.Warn("skipping DNS server restart due to failed files update")
-					continue
+			settings := l.GetSettings()
+			if l.GetStatus() == constants.Running {
+				if err := l.updateFiles(ctx, settings); err != nil {
+					l.logger.Warn("updating block lists failed, skipping: " + err.Error())
 				}
 			}
-
-			_, _ = l.statusManager.ApplyStatus(ctx, constants.Stopped)
-			_, _ = l.statusManager.ApplyStatus(ctx, constants.Running)
-
-			settings := l.GetSettings()
-			timer.Reset(*settings.DoT.UpdatePeriod)
+			timer.Reset(*settings.UpdatePeriod)
 		case <-l.updateTicker:
 			if !timer.Stop() {
 				<-timer.C
 			}
 			timerIsStopped = true
 			settings := l.GetSettings()
-			newUpdatePeriod := *settings.DoT.UpdatePeriod
+			newUpdatePeriod := *settings.UpdatePeriod
 			if newUpdatePeriod == 0 {
 				continue
 			}

internal/dns/update.go

@@ -6,13 +6,12 @@ import (
 
 	"github.com/qdm12/dns/v2/pkg/blockbuilder"
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/update"
+	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (l *Loop) updateFiles(ctx context.Context) (err error) {
-	settings := l.GetSettings()
-
+func (l *Loop) updateFiles(ctx context.Context, settings settings.DNS) (err error) {
 	l.logger.Info("downloading hostnames and IP block lists")
-	blacklistSettings := settings.DoT.Blacklist.ToBlockBuilderSettings(l.client)
+	blacklistSettings := settings.Blacklist.ToBlockBuilderSettings(l.client)
 
 	blockBuilder, err := blockbuilder.New(blacklistSettings)
 	if err != nil {

internal/firewall/enable.go

@@ -22,9 +22,7 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 
 	if !enabled {
 		c.logger.Info("disabling...")
-		if err = c.disable(ctx); err != nil {
-			return fmt.Errorf("disabling firewall: %w", err)
-		}
+		c.restore(ctx)
 		c.enabled = false
 		c.logger.Info("disabled successfully")
 		return nil
@@ -41,64 +39,33 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 	return nil
 }
 
-func (c *Config) disable(ctx context.Context) (err error) {
-	if err = c.clearAllRules(ctx); err != nil {
-		return fmt.Errorf("clearing all rules: %w", err)
-	}
-	if err = c.setIPv4AllPolicies(ctx, "ACCEPT"); err != nil {
-		return fmt.Errorf("setting ipv4 policies: %w", err)
-	}
-	if err = c.setIPv6AllPolicies(ctx, "ACCEPT"); err != nil {
-		return fmt.Errorf("setting ipv6 policies: %w", err)
-	}
-
-	const remove = true
-	err = c.redirectPorts(ctx, remove)
-	if err != nil {
-		return fmt.Errorf("removing port redirections: %w", err)
-	}
-
-	return nil
-}
-
-// To use in defered call when enabling the firewall.
-func (c *Config) fallbackToDisabled(ctx context.Context) {
-	if ctx.Err() != nil {
-		return
-	}
-	if err := c.disable(ctx); err != nil {
-		c.logger.Error("failed reversing firewall changes: " + err.Error())
-	}
-}
-
 func (c *Config) enable(ctx context.Context) (err error) {
-	touched := false
-	if err = c.setIPv4AllPolicies(ctx, "DROP"); err != nil {
+	c.restore, err = c.impl.SaveAndRestore(ctx)
+	if err != nil {
+		return fmt.Errorf("saving firewall rules: %w", err)
+	}
+
+	defer func() {
+		if err != nil {
+			c.restore(context.Background())
+		}
+	}()
+
+	if err = c.impl.SetBaseChainsPolicy(ctx, "DROP"); err != nil {
 		return err
 	}
-	touched = true
 
-	if err = c.setIPv6AllPolicies(ctx, "DROP"); err != nil {
+	// Loopback traffic
+	if err = c.impl.AcceptInputThroughInterface(ctx, "lo"); err != nil {
 		return err
 	}
 
 	const remove = false
-
-	defer func() {
-		if touched && err != nil {
-			c.fallbackToDisabled(ctx)
-		}
-	}()
-
-	// Loopback traffic
-	if err = c.acceptInputThroughInterface(ctx, "lo", remove); err != nil {
-		return err
-	}
-	if err = c.acceptOutputThroughInterface(ctx, "lo", remove); err != nil {
+	if err = c.impl.AcceptOutputThroughInterface(ctx, "lo", remove); err != nil {
 		return err
 	}
 
-	if err = c.acceptEstablishedRelatedTraffic(ctx, remove); err != nil {
+	if err = c.impl.AcceptEstablishedRelatedTraffic(ctx); err != nil {
 		return err
 	}
 
@@ -108,7 +75,9 @@ func (c *Config) enable(ctx context.Context) (err error) {
 
 	localInterfaces := make(map[string]struct{}, len(c.localNetworks))
 	for _, network := range c.localNetworks {
-		if err := c.acceptOutputFromIPToSubnet(ctx, network.InterfaceName, network.IP, network.IPNet, remove); err != nil {
+		err = c.impl.AcceptOutputFromIPToSubnet(ctx,
+			network.InterfaceName, network.IP, network.IPNet, remove)
+		if err != nil {
 			return err
 		}
 
@@ -117,7 +86,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 			continue
 		}
 		localInterfaces[network.InterfaceName] = struct{}{}
-		err = c.acceptIpv6MulticastOutput(ctx, network.InterfaceName, remove)
+		err = c.impl.AcceptIpv6MulticastOutput(ctx, network.InterfaceName)
 		if err != nil {
 			return fmt.Errorf("accepting IPv6 multicast output: %w", err)
 		}
@@ -130,7 +99,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 	// Allows packets from any IP address to go through eth0 / local network
 	// to reach Gluetun.
 	for _, network := range c.localNetworks {
-		if err := c.acceptInputToSubnet(ctx, network.InterfaceName, network.IPNet, remove); err != nil {
+		if err := c.impl.AcceptInputToSubnet(ctx, network.InterfaceName, network.IPNet); err != nil {
 			return err
 		}
 	}
@@ -139,12 +108,12 @@ func (c *Config) enable(ctx context.Context) (err error) {
 		return err
 	}
 
-	err = c.redirectPorts(ctx, remove)
+	err = c.redirectPorts(ctx)
 	if err != nil {
 		return fmt.Errorf("redirecting ports: %w", err)
 	}
 
-	if err := c.runUserPostRules(ctx, c.customRulesPath, remove); err != nil {
+	if err := c.impl.RunUserPostRules(ctx, c.customRulesPath); err != nil {
 		return fmt.Errorf("running user defined post firewall rules: %w", err)
 	}
 
@@ -164,7 +133,7 @@ func (c *Config) allowVPNIP(ctx context.Context) (err error) {
 			continue
 		}
 		interfacesSeen[defaultRoute.NetInterface] = struct{}{}
-		err = c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove)
+		err = c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove)
 		if err != nil {
 			return fmt.Errorf("accepting output traffic through VPN: %w", err)
 		}
@@ -186,7 +155,7 @@ func (c *Config) allowOutboundSubnets(ctx context.Context) (err error) {
 			firewallUpdated = true
 
 			const remove = false
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subnet, remove)
 			if err != nil {
 				return err
@@ -204,7 +173,7 @@ func (c *Config) allowInputPorts(ctx context.Context) (err error) {
 	for port, netInterfaces := range c.allowedInputPorts {
 		for netInterface := range netInterfaces {
 			const remove = false
-			err = c.acceptInputToPort(ctx, netInterface, port, remove)
+			err = c.impl.AcceptInputToPort(ctx, netInterface, port, remove)
 			if err != nil {
 				return fmt.Errorf("accepting input port %d on interface %s: %w",
 					port, netInterface, err)
@@ -214,9 +183,10 @@ func (c *Config) allowInputPorts(ctx context.Context) (err error) {
 	return nil
 }
 
-func (c *Config) redirectPorts(ctx context.Context, remove bool) (err error) {
+func (c *Config) redirectPorts(ctx context.Context) (err error) {
 	for _, portRedirection := range c.portRedirections {
-		err = c.redirectPort(ctx, portRedirection.interfaceName, portRedirection.sourcePort,
+		const remove = false
+		err = c.impl.RedirectPort(ctx, portRedirection.interfaceName, portRedirection.sourcePort,
 			portRedirection.destinationPort, remove)
 		if err != nil {
 			return err

internal/firewall/firewall.go

@@ -2,28 +2,28 @@ package firewall
 
 import (
 	"context"
+	"fmt"
 	"net/netip"
 	"sync"
 
+	"github.com/qdm12/gluetun/internal/firewall/iptables"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/routing"
 )
 
-type Config struct { //nolint:maligned
-	runner         CmdRunner
-	logger         Logger
-	iptablesMutex  sync.Mutex
-	ip6tablesMutex sync.Mutex
-	defaultRoutes  []routing.DefaultRoute
-	localNetworks  []routing.LocalNetwork
+type Config struct {
+	runner        CmdRunner
+	logger        Logger
+	defaultRoutes []routing.DefaultRoute
+	localNetworks []routing.LocalNetwork
 
-	// Fixed state
-	ipTables        string
-	ip6Tables       string
+	// Fixed
+	impl            firewallImpl
 	customRulesPath string
 
 	// State
 	enabled           bool
+	restore           func(context.Context)
 	vpnConnection     models.Connection
 	vpnIntf           string
 	outboundSubnets   []netip.Prefix
@@ -38,25 +38,19 @@ func NewConfig(ctx context.Context, logger Logger,
 	runner CmdRunner, defaultRoutes []routing.DefaultRoute,
 	localNetworks []routing.LocalNetwork,
 ) (config *Config, err error) {
-	iptables, err := checkIptablesSupport(ctx, runner, "iptables", "iptables-nft", "iptables-legacy")
+	impl, err := iptables.New(ctx, runner, logger)
 	if err != nil {
-		return nil, err
-	}
-
-	ip6tables, err := findIP6tablesSupported(ctx, runner)
-	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("creating iptables firewall: %w", err)
 	}
 
 	return &Config{
 		runner:            runner,
 		logger:            logger,
 		allowedInputPorts: make(map[uint16]map[string]struct{}),
-		ipTables:          iptables,
-		ip6Tables:         ip6tables,
-		customRulesPath:   "/iptables/post-rules.txt",
 		// Obtained from routing
-		defaultRoutes: defaultRoutes,
-		localNetworks: localNetworks,
+		defaultRoutes:   defaultRoutes,
+		localNetworks:   localNetworks,
+		impl:            impl,
+		customRulesPath: "/iptables/post-rules.txt",
 	}, nil
 }

internal/firewall/interfaces.go

@@ -1,6 +1,12 @@
 package firewall
 
-import "os/exec"
+import (
+	"context"
+	"net/netip"
+	"os/exec"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
 
 type CmdRunner interface {
 	Run(cmd *exec.Cmd) (output string, err error)
@@ -12,3 +18,24 @@ type Logger interface {
 	Warn(s string)
 	Error(s string)
 }
+
+type firewallImpl interface { //nolint:interfacebloat
+	SaveAndRestore(ctx context.Context) (restore func(context.Context), err error)
+	AcceptEstablishedRelatedTraffic(ctx context.Context) error
+	AcceptInputThroughInterface(ctx context.Context, intf string) error
+	AcceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error
+	AcceptInputToSubnet(ctx context.Context, intf string, subnet netip.Prefix) error
+	AcceptIpv6MulticastOutput(ctx context.Context, intf string) error
+	AcceptOutputFromIPToSubnet(ctx context.Context, intf string, assignedIP netip.Addr,
+		subnet netip.Prefix, remove bool) error
+	AcceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error
+	AcceptOutputTrafficToVPN(ctx context.Context, intf string,
+		connection models.Connection, remove bool) error
+	RedirectPort(ctx context.Context, intf string, sourcePort,
+		destinationPort uint16, remove bool) error
+	RunUserPostRules(ctx context.Context, customRulesPath string) error
+	SetBaseChainsPolicy(ctx context.Context, policy string) error
+	TempDropOutputTCPRST(ctx context.Context, src, dst netip.AddrPort, excludeMark int) (
+		revert func(ctx context.Context) error, err error)
+	Version(ctx context.Context) (version string, err error)
+}

internal/firewall/iptables/atomic.go

@@ -0,0 +1,85 @@
+package iptables
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+// SaveAndRestore saves the current iptables and ip6tables rules and
+// returns a restore function that can be called to restore the saved rules.
+func (c *Config) SaveAndRestore(ctx context.Context) (restore func(context.Context), err error) {
+	c.iptablesMutex.Lock()
+	c.ip6tablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+	defer c.ip6tablesMutex.Unlock()
+
+	return c.saveAndRestore(ctx)
+}
+
+// callers MUST always lock both the [Config] iptablesMutex and the ip6tablesMutex
+// before calling this function. Note the restore function does not interact with mutexes
+// so the caller must make sure the mutexes are locked when calling the restore function.
+func (c *Config) saveAndRestore(ctx context.Context) (restore func(context.Context), err error) {
+	restoreIPv4, err := c.saveAndRestoreIPv4(ctx)
+	if err != nil {
+		return nil, err
+	}
+	restoreIPv6, err := c.saveAndRestoreIPv6(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	restore = func(ctx context.Context) {
+		restoreIPv4(ctx)
+		if restoreIPv6 != nil {
+			restoreIPv6(ctx)
+		}
+	}
+	return restore, nil
+}
+
+// Callers of saveAndRestoreIPv4 MUST always lock the [Config] iptablesMutex
+// before calling this function.
+func (c *Config) saveAndRestoreIPv4(ctx context.Context) (restore func(context.Context), err error) {
+	cmd := exec.CommandContext(ctx, c.ipTables+"-save") //nolint:gosec
+	data, err := c.runner.Run(cmd)
+	if err != nil {
+		return nil, fmt.Errorf("saving IPv4 iptables: %w", err)
+	}
+
+	restore = func(ctx context.Context) {
+		cmd := exec.CommandContext(ctx, c.ipTables+"-restore") //nolint:gosec
+		cmd.Stdin = strings.NewReader(data)
+		output, err := c.runner.Run(cmd)
+		if err != nil {
+			c.logger.Warn(fmt.Sprintf("restoring IPv4 iptables failed: %v: %s", err, output))
+		}
+	}
+	return restore, nil
+}
+
+// Callers of saveAndRestoreIPv6 MUST always lock the [Config] ip6tablesMutex
+// before calling this function.
+func (c *Config) saveAndRestoreIPv6(ctx context.Context) (restore func(context.Context), err error) {
+	if c.ip6Tables == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	cmd := exec.CommandContext(ctx, c.ip6Tables+"-save") //nolint:gosec
+	data, err := c.runner.Run(cmd)
+	if err != nil {
+		return nil, fmt.Errorf("saving IPv6 iptables: %w", err)
+	}
+
+	restore = func(ctx context.Context) {
+		cmd = exec.CommandContext(ctx, c.ip6Tables+"-restore") //nolint:gosec
+		cmd.Stdin = strings.NewReader(data)
+		output, err := c.runner.Run(cmd)
+		if err != nil {
+			c.logger.Warn(fmt.Sprintf("restoring IPv6 iptables failed: %v: %s", err, output))
+		}
+	}
+	return restore, nil
+}

internal/firewall/iptables/cmd_matcher_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"fmt"

internal/firewall/iptables/delete.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -16,7 +16,7 @@ func isDeleteMatchInstruction(instruction string) bool {
 	fields := strings.Fields(instruction)
 	for i, field := range fields {
 		switch {
-		case field != "-D" && field != "--delete": //nolint:goconst
+		case field != "-D" && field != "--delete":
 			continue
 		case i == len(fields)-1: // malformed: missing chain name
 			return false

internal/firewall/iptables/delete_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -69,8 +69,8 @@ func Test_deleteIPTablesRule(t *testing.T) {
 		"invalid_instruction": {
 			instruction: "invalid",
 			errWrapped:  ErrIptablesCommandMalformed,
-			errMessage: "parsing iptables command: iptables command is malformed: " +
-				"fields count 1 is not even: \"invalid\"",
+			errMessage: "parsing iptables command: parsing \"invalid\": " +
+				"iptables command is malformed: flag \"invalid\" requires a value, but got none",
 		},
 		"list_error": {
 			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",

internal/firewall/iptables/firewall.go

@@ -0,0 +1,51 @@
+package iptables
+
+import (
+	"context"
+	"sync"
+
+	"github.com/qdm12/gluetun/internal/mod"
+)
+
+type Config struct {
+	runner         CmdRunner
+	logger         Logger
+	iptablesMutex  sync.Mutex
+	ip6tablesMutex sync.Mutex
+
+	// Fixed state
+	ipTables  string
+	ip6Tables string
+	nftables  bool
+	xtMark    bool
+}
+
+func New(ctx context.Context, runner CmdRunner, logger Logger) (*Config, error) {
+	iptables, err := checkIptablesSupport(ctx, runner, "iptables", "iptables-nft", "iptables-legacy")
+	if err != nil {
+		return nil, err
+	}
+
+	ip6tables, err := findIP6tablesSupported(ctx, runner)
+	if err != nil {
+		return nil, err
+	}
+
+	modules := map[string]bool{
+		"xt_mark":   false,
+		"nf_tables": false,
+	}
+	for module := range modules {
+		err := mod.Probe(module)
+		modules[module] = err == nil
+	}
+
+	return &Config{
+		runner:    runner,
+		logger:    logger,
+		ipTables:  iptables,
+		ip6Tables: ip6tables,
+		nftables:  modules["nf_tables"],
+		xtMark:    modules["xt_mark"],
+	}, nil
+}

internal/firewall/iptables/interfaces.go

@@ -0,0 +1,14 @@
+package iptables
+
+import "os/exec"
+
+type CmdRunner interface {
+	Run(cmd *exec.Cmd) (output string, err error)
+}
+
+type Logger interface {
+	Debug(s string)
+	Info(s string)
+	Warn(s string)
+	Error(s string)
+}

internal/firewall/iptables/ip6tables.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -14,8 +14,8 @@ import (
 func findIP6tablesSupported(ctx context.Context, runner CmdRunner) (
 	ip6tablesPath string, err error,
 ) {
-	ip6tablesPath, err = checkIptablesSupport(ctx, runner, "ip6tables", "ip6tables-nft", "ip6tables-legacy")
-	if errors.Is(err, ErrIPTablesNotSupported) {
+	ip6tablesPath, err = checkIptablesSupport(ctx, runner, "ip6tables", "ip6tables-legacy")
+	if errors.Is(err, ErrNotSupported) {
 		return "", nil
 	} else if err != nil {
 		return "", err
@@ -24,8 +24,23 @@ func findIP6tablesSupported(ctx context.Context, runner CmdRunner) (
 }
 
 func (c *Config) runIP6tablesInstructions(ctx context.Context, instructions []string) error {
+	c.ip6tablesMutex.Lock() // only one ip6tables command at once
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestoreIPv6(ctx)
+	if err != nil {
+		return err
+	}
+	err = c.runIP6tablesInstructionsNoSave(ctx, instructions)
+	if err != nil {
+		restore(ctx)
+	}
+	return err
+}
+
+func (c *Config) runIP6tablesInstructionsNoSave(ctx context.Context, instructions []string) error {
 	for _, instruction := range instructions {
-		if err := c.runIP6tablesInstruction(ctx, instruction); err != nil {
+		if err := c.runIP6tablesInstructionNoSave(ctx, instruction); err != nil {
 			return err
 		}
 	}
@@ -33,11 +48,24 @@ func (c *Config) runIP6tablesInstructions(ctx context.Context, instructions []st
 }
 
 func (c *Config) runIP6tablesInstruction(ctx context.Context, instruction string) error {
+	c.ip6tablesMutex.Lock() // only one ip6tables command at once
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestoreIPv6(ctx)
+	if err != nil {
+		return err
+	}
+	err = c.runIP6tablesInstructionNoSave(ctx, instruction)
+	if err != nil {
+		restore(ctx)
+	}
+	return err
+}
+
+func (c *Config) runIP6tablesInstructionNoSave(ctx context.Context, instruction string) error {
 	if c.ip6Tables == "" {
 		return nil
 	}
-	c.ip6tablesMutex.Lock() // only one ip6tables command at once
-	defer c.ip6tablesMutex.Unlock()
 
 	if isDeleteMatchInstruction(instruction) {
 		return deleteIPTablesRule(ctx, c.ip6Tables, instruction,
@@ -53,18 +81,3 @@ func (c *Config) runIP6tablesInstruction(ctx context.Context, instruction string
 	}
 	return nil
 }
-
-var ErrPolicyNotValid = errors.New("policy is not valid")
-
-func (c *Config) setIPv6AllPolicies(ctx context.Context, policy string) error {
-	switch policy {
-	case "ACCEPT", "DROP": //nolint:goconst
-	default:
-		return fmt.Errorf("%w: %s", ErrPolicyNotValid, policy)
-	}
-	return c.runIP6tablesInstructions(ctx, []string{
-		"--policy INPUT " + policy,
-		"--policy OUTPUT " + policy,
-		"--policy FORWARD " + policy,
-	})
-}

internal/firewall/iptables/iptables.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -26,22 +26,6 @@ func appendOrDelete(remove bool) string {
 	return "--append"
 }
 
-// flipRule changes an append rule in a delete rule or a delete rule into an
-// append rule.
-func flipRule(rule string) string {
-	switch {
-	case strings.HasPrefix(rule, "-A"):
-		return strings.Replace(rule, "-A", "-D", 1)
-	case strings.HasPrefix(rule, "--append"):
-		return strings.Replace(rule, "--append", "-D", 1)
-	case strings.HasPrefix(rule, "-D"):
-		return strings.Replace(rule, "-D", "-A", 1)
-	case strings.HasPrefix(rule, "--delete"):
-		return strings.Replace(rule, "--delete", "-A", 1)
-	}
-	return rule
-}
-
 // Version obtains the version of the installed iptables.
 func (c *Config) Version(ctx context.Context) (string, error) {
 	cmd := exec.CommandContext(ctx, c.ipTables, "--version") //nolint:gosec
@@ -54,12 +38,28 @@ func (c *Config) Version(ctx context.Context) (string, error) {
 	if len(words) < minWords {
 		return "", fmt.Errorf("%w: %s", ErrIPTablesVersionTooShort, output)
 	}
-	return words[1], nil
+	return "iptables " + words[1], nil
 }
 
 func (c *Config) runIptablesInstructions(ctx context.Context, instructions []string) error {
+	c.iptablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+
+	restore, err := c.saveAndRestoreIPv4(ctx)
+	if err != nil {
+		return err
+	}
+
+	err = c.runIptablesInstructionsNoSave(ctx, instructions)
+	if err != nil {
+		restore(ctx)
+	}
+	return err
+}
+
+func (c *Config) runIptablesInstructionsNoSave(ctx context.Context, instructions []string) error {
 	for _, instruction := range instructions {
-		if err := c.runIptablesInstruction(ctx, instruction); err != nil {
+		if err := c.runIptablesInstructionNoSave(ctx, instruction); err != nil {
 			return err
 		}
 	}
@@ -70,6 +70,19 @@ func (c *Config) runIptablesInstruction(ctx context.Context, instruction string)
 	c.iptablesMutex.Lock() // only one iptables command at once
 	defer c.iptablesMutex.Unlock()
 
+	restore, err := c.saveAndRestoreIPv4(ctx)
+	if err != nil {
+		return err
+	}
+
+	err = c.runIptablesInstructionNoSave(ctx, instruction)
+	if err != nil {
+		restore(ctx)
+	}
+	return err
+}
+
+func (c *Config) runIptablesInstructionNoSave(ctx context.Context, instruction string) error {
 	if isDeleteMatchInstruction(instruction) {
 		return deleteIPTablesRule(ctx, c.ipTables, instruction,
 			c.runner, c.logger)
@@ -85,42 +98,33 @@ func (c *Config) runIptablesInstruction(ctx context.Context, instruction string)
 	return nil
 }
 
-func (c *Config) clearAllRules(ctx context.Context) error {
-	return c.runMixedIptablesInstructions(ctx, []string{
-		"--flush",        // flush all chains
-		"--delete-chain", // delete all chains
-	})
-}
-
-func (c *Config) setIPv4AllPolicies(ctx context.Context, policy string) error {
+func (c *Config) SetBaseChainsPolicy(ctx context.Context, policy string) error {
+	policy = strings.ToUpper(policy)
 	switch policy {
 	case "ACCEPT", "DROP":
 	default:
 		return fmt.Errorf("%w: %s", ErrPolicyUnknown, policy)
 	}
-	return c.runIptablesInstructions(ctx, []string{
+	return c.runMixedIptablesInstructions(ctx, []string{
 		"--policy INPUT " + policy,
 		"--policy OUTPUT " + policy,
 		"--policy FORWARD " + policy,
 	})
 }
 
-func (c *Config) acceptInputThroughInterface(ctx context.Context, intf string, remove bool) error {
+func (c *Config) AcceptInputThroughInterface(ctx context.Context, intf string) error {
 	return c.runMixedIptablesInstruction(ctx, fmt.Sprintf(
-		"%s INPUT -i %s -j ACCEPT", appendOrDelete(remove), intf,
-	))
+		"--append INPUT -i %s -j ACCEPT", intf))
 }
 
-func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
-	destination netip.Prefix, remove bool,
-) error {
+func (c *Config) AcceptInputToSubnet(ctx context.Context, intf string, destination netip.Prefix) error {
 	interfaceFlag := "-i " + intf
 	if intf == "*" { // all interfaces
 		interfaceFlag = ""
 	}
 
-	instruction := fmt.Sprintf("%s INPUT %s -d %s -j ACCEPT",
-		appendOrDelete(remove), interfaceFlag, destination.String())
+	instruction := fmt.Sprintf("--append INPUT %s -d %s -j ACCEPT",
+		interfaceFlag, destination.String())
 
 	if destination.Addr().Is4() {
 		return c.runIptablesInstruction(ctx, instruction)
@@ -131,25 +135,25 @@ func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-func (c *Config) acceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error {
+func (c *Config) AcceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error {
 	return c.runMixedIptablesInstruction(ctx, fmt.Sprintf(
 		"%s OUTPUT -o %s -j ACCEPT", appendOrDelete(remove), intf,
 	))
 }
 
-func (c *Config) acceptEstablishedRelatedTraffic(ctx context.Context, remove bool) error {
+func (c *Config) AcceptEstablishedRelatedTraffic(ctx context.Context) error {
 	return c.runMixedIptablesInstructions(ctx, []string{
-		fmt.Sprintf("%s OUTPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT", appendOrDelete(remove)),
-		fmt.Sprintf("%s INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT", appendOrDelete(remove)),
+		"--append OUTPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT",
+		"--append INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT",
 	})
 }
 
-func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
+func (c *Config) AcceptOutputTrafficToVPN(ctx context.Context,
 	defaultInterface string, connection models.Connection, remove bool,
 ) error {
 	protocol := connection.Protocol
 	if protocol == "tcp-client" {
-		protocol = "tcp" //nolint:goconst
+		protocol = "tcp"
 	}
 	instruction := fmt.Sprintf("%s OUTPUT -d %s -o %s -p %s -m %s --dport %d -j ACCEPT",
 		appendOrDelete(remove), connection.IP, defaultInterface, protocol,
@@ -162,8 +166,11 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
+// AcceptOutputFromIPToSubnet accepts outgoing traffic from sourceIP to destinationSubnet
+// on the interface intf. If intf is empty, it is set to "*" which means all interfaces.
+// If remove is true, the rule is removed instead of added.
 // Thanks to @npawelek.
-func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
+func (c *Config) AcceptOutputFromIPToSubnet(ctx context.Context,
 	intf string, sourceIP netip.Addr, destinationSubnet netip.Prefix, remove bool,
 ) error {
 	doIPv4 := sourceIP.Is4() && destinationSubnet.Addr().Is4()
@@ -184,21 +191,24 @@ func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-// NDP uses multicast address (theres no broadcast in IPv6 like ARP uses in IPv4).
-func (c *Config) acceptIpv6MulticastOutput(ctx context.Context,
-	intf string, remove bool,
-) error {
+// AcceptIpv6MulticastOutput accepts outgoing traffic to the IPv6 multicast address
+// ff02::1:ff00:0/104, which is used for NDP (Neighbor Discovery Protocol) to resolve
+// IPv6 addresses to MAC addresses. If intf is empty, it is set to "*" which means
+// all interfaces. If remove is true, the rule is removed instead of added.
+func (c *Config) AcceptIpv6MulticastOutput(ctx context.Context, intf string) error {
 	interfaceFlag := "-o " + intf
 	if intf == "*" { // all interfaces
 		interfaceFlag = ""
 	}
-	instruction := fmt.Sprintf("%s OUTPUT %s -d ff02::1:ff00:0/104 -j ACCEPT",
-		appendOrDelete(remove), interfaceFlag)
+	instruction := fmt.Sprintf("--append OUTPUT %s -d ff02::1:ff00:0/104 -j ACCEPT", interfaceFlag)
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-// Used for port forwarding, with intf set to tun.
-func (c *Config) acceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error {
+// AcceptInputToPort accepts incoming traffic on the specified port, for both TCP and UDP
+// protocols, on the interface intf. If intf is empty, it is set to "*" which means all interfaces.
+// If remove is true, the rule is removed instead of added. This is used for port forwarding, with
+// intf set to the VPN tunnel interface.
+func (c *Config) AcceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error {
 	interfaceFlag := "-i " + intf
 	if intf == "*" { // all interfaces
 		interfaceFlag = ""
@@ -209,8 +219,12 @@ func (c *Config) acceptInputToPort(ctx context.Context, intf string, port uint16
 	})
 }
 
-// Used for VPN server side port forwarding, with intf set to the VPN tunnel interface.
-func (c *Config) redirectPort(ctx context.Context, intf string,
+// RedirectPort redirects incoming traffic on the specified source port to the
+// specified destination port, for both TCP and UDP protocols, on the interface intf.
+// If intf is empty, it is set to "*" which means all interfaces. If remove is true,
+// the redirection is removed instead of added. This is used for VPN server side
+// port forwarding, with intf set to the VPN tunnel interface.
+func (c *Config) RedirectPort(ctx context.Context, intf string,
 	sourcePort, destinationPort uint16, remove bool,
 ) (err error) {
 	interfaceFlag := "-i " + intf
@@ -218,7 +232,17 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 		interfaceFlag = ""
 	}
 
-	err = c.runIptablesInstructions(ctx, []string{
+	c.iptablesMutex.Lock()
+	c.ip6tablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestore(ctx)
+	if err != nil {
+		return err
+	}
+
+	err = c.runIptablesInstructionsNoSave(ctx, []string{
 		fmt.Sprintf("-t nat %s PREROUTING %s -p tcp --dport %d -j REDIRECT --to-ports %d",
 			appendOrDelete(remove), interfaceFlag, sourcePort, destinationPort),
 		fmt.Sprintf("%s INPUT %s -p tcp -m tcp --dport %d -j ACCEPT",
@@ -229,11 +253,12 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 			appendOrDelete(remove), interfaceFlag, destinationPort),
 	})
 	if err != nil {
+		restore(ctx)
 		return fmt.Errorf("redirecting IPv4 source port %d to destination port %d on interface %s: %w",
 			sourcePort, destinationPort, intf, err)
 	}
 
-	err = c.runIP6tablesInstructions(ctx, []string{
+	err = c.runIP6tablesInstructionsNoSave(ctx, []string{
 		fmt.Sprintf("-t nat %s PREROUTING %s -p tcp --dport %d -j REDIRECT --to-ports %d",
 			appendOrDelete(remove), interfaceFlag, sourcePort, destinationPort),
 		fmt.Sprintf("%s INPUT %s -p tcp -m tcp --dport %d -j ACCEPT",
@@ -244,6 +269,7 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 			appendOrDelete(remove), interfaceFlag, destinationPort),
 	})
 	if err != nil {
+		restore(ctx) // just in case
 		errMessage := err.Error()
 		if strings.Contains(errMessage, "can't initialize ip6tables table `nat': Table does not exist") {
 			if !remove {
@@ -257,7 +283,7 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 	return nil
 }
 
-func (c *Config) runUserPostRules(ctx context.Context, filepath string, remove bool) error {
+func (c *Config) RunUserPostRules(ctx context.Context, filepath string) error {
 	file, err := os.OpenFile(filepath, os.O_RDONLY, 0)
 	if os.IsNotExist(err) {
 		return nil
@@ -273,16 +299,17 @@ func (c *Config) runUserPostRules(ctx context.Context, filepath string, remove b
 		return err
 	}
 	lines := strings.Split(string(b), "\n")
-	successfulRules := []string{}
-	defer func() {
-		// transaction-like rollback
-		if err == nil || ctx.Err() != nil {
-			return
-		}
-		for _, rule := range successfulRules {
-			_ = c.runIptablesInstruction(ctx, flipRule(rule))
-		}
-	}()
+
+	c.iptablesMutex.Lock()
+	c.ip6tablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestore(ctx)
+	if err != nil {
+		return err
+	}
+
 	for _, line := range lines {
 		var ipv4 bool
 		var rule string
@@ -309,23 +336,18 @@ func (c *Config) runUserPostRules(ctx context.Context, filepath string, remove b
 			continue
 		}
 
-		if remove {
-			rule = flipRule(rule)
-		}
-
 		switch {
 		case ipv4:
-			err = c.runIptablesInstruction(ctx, rule)
+			err = c.runIptablesInstructionNoSave(ctx, rule)
 		case c.ip6Tables == "":
 			err = fmt.Errorf("running user ip6tables rule: %w", ErrNeedIP6Tables)
 		default: // ipv6
-			err = c.runIP6tablesInstruction(ctx, rule)
+			err = c.runIP6tablesInstructionNoSave(ctx, rule)
 		}
 		if err != nil {
+			restore(ctx)
 			return err
 		}
-
-		successfulRules = append(successfulRules, rule)
 	}
 	return nil
 }

internal/firewall/iptables/iptablesmix.go

@@ -0,0 +1,49 @@
+package iptables
+
+import (
+	"context"
+)
+
+func (c *Config) runMixedIptablesInstructions(ctx context.Context, instructions []string) error {
+	c.iptablesMutex.Lock()
+	c.ip6tablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestore(ctx)
+	if err != nil {
+		return err
+	}
+
+	for _, instruction := range instructions {
+		if err := c.runMixedIptablesInstructionNoSave(ctx, instruction); err != nil {
+			restore(ctx)
+			return err
+		}
+	}
+	return nil
+}
+
+func (c *Config) runMixedIptablesInstruction(ctx context.Context, instruction string) error {
+	c.iptablesMutex.Lock()
+	c.ip6tablesMutex.Lock()
+	defer c.iptablesMutex.Unlock()
+	defer c.ip6tablesMutex.Unlock()
+
+	restore, err := c.saveAndRestore(ctx)
+	if err != nil {
+		return err
+	}
+	err = c.runMixedIptablesInstructionNoSave(ctx, instruction)
+	if err != nil {
+		restore(ctx)
+	}
+	return err
+}
+
+func (c *Config) runMixedIptablesInstructionNoSave(ctx context.Context, instruction string) error {
+	if err := c.runIptablesInstructionNoSave(ctx, instruction); err != nil {
+		return err
+	}
+	return c.runIP6tablesInstructionNoSave(ctx, instruction)
+}

internal/firewall/iptables/list.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"errors"
@@ -26,10 +26,18 @@ type chainRule struct {
 	inputInterface  string       // input interface, for example "tun0" or "*""
 	outputInterface string       // output interface, for example "eth0" or "*""
 	source          netip.Prefix // source IP CIDR, for example 0.0.0.0/0. Must be valid.
+	sourcePort      uint16       // Not specified if set to zero.
 	destination     netip.Prefix // destination IP CIDR, for example 0.0.0.0/0. Must be valid.
 	destinationPort uint16       // Not specified if set to zero.
 	redirPorts      []uint16     // Not specified if empty.
 	ctstate         []string     // for example ["RELATED","ESTABLISHED"]. Can be empty.
+	tcpFlags        tcpFlags
+	mark            mark
+}
+
+type mark struct {
+	invert bool
+	value  uint
 }
 
 var ErrChainListMalformed = errors.New("iptables chain list output is malformed")
@@ -241,19 +249,23 @@ func parseChainRuleField(fieldIndex int, field string, rule *chainRule) (err err
 }
 
 func parseChainRuleOptionalFields(optionalFields []string, rule *chainRule) (err error) {
-	for i := 0; i < len(optionalFields); i++ {
-		key := optionalFields[i]
-		switch key {
-		case "tcp", "udp":
+	i := 0
+	for i < len(optionalFields) {
+		switch optionalFields[i] {
+		case "udp":
 			i++
-			value := optionalFields[i]
-			value = strings.TrimPrefix(value, "dpt:")
-			const base, bitLength = 10, 16
-			destinationPort, err := strconv.ParseUint(value, base, bitLength)
+			consumed, err := parseUDPOptional(optionalFields[i:], rule)
 			if err != nil {
-				return fmt.Errorf("parsing destination port %q: %w", value, err)
+				return fmt.Errorf("parsing UDP optional fields: %w", err)
 			}
-			rule.destinationPort = uint16(destinationPort)
+			i += consumed
+		case "tcp":
+			i++
+			consumed, err := parseTCPOptional(optionalFields[i:], rule)
+			if err != nil {
+				return fmt.Errorf("parsing TCP optional fields: %w", err)
+			}
+			i += consumed
 		case "redir":
 			i++
 			switch optionalFields[i] {
@@ -264,20 +276,136 @@ func parseChainRuleOptionalFields(optionalFields []string, rule *chainRule) (err
 					return fmt.Errorf("parsing redirection ports: %w", err)
 				}
 				rule.redirPorts = ports
+				i++
 			default:
-				return fmt.Errorf("%w: unexpected optional field: %s",
-					ErrChainRuleMalformed, optionalFields[i])
+				return fmt.Errorf("%w: unexpected %q after redir",
+					ErrChainRuleMalformed, optionalFields[1])
 			}
 		case "ctstate":
 			i++
 			rule.ctstate = strings.Split(optionalFields[i], ",")
+			i++
+		case "mark":
+			i++
+			mark, consumed, err := parseMark(optionalFields[i:])
+			if err != nil {
+				return fmt.Errorf("parsing mark: %w", err)
+			}
+			rule.mark = mark
+			i += consumed
 		default:
-			return fmt.Errorf("%w: unexpected optional field: %s", ErrChainRuleMalformed, key)
+			return fmt.Errorf("%w: unexpected optional field: %s",
+				ErrChainRuleMalformed, optionalFields[i])
 		}
 	}
 	return nil
 }
 
+var errUDPOptionalUnknown = errors.New("unknown UDP optional field")
+
+func parseUDPOptional(optionalFields []string, rule *chainRule) (consumed int, err error) {
+	for _, value := range optionalFields {
+		if !strings.ContainsRune(value, ':') {
+			// no longer a UDP-associated option
+			return consumed, nil
+		}
+		switch {
+		case strings.HasPrefix(value, "dpt:"):
+			rule.destinationPort, err = parseDestinationPort(value)
+			if err != nil {
+				return 0, fmt.Errorf("parsing destination port: %w", err)
+			}
+			consumed++
+		case strings.HasPrefix(value, "spt:"):
+			rule.sourcePort, err = parseSourcePort(value)
+			if err != nil {
+				return 0, fmt.Errorf("parsing source port: %w", err)
+			}
+			consumed++
+		default:
+			return 0, fmt.Errorf("%w: %s", errUDPOptionalUnknown, value)
+		}
+	}
+	return consumed, nil
+}
+
+var errTCPOptionalUnknown = errors.New("unknown TCP optional field")
+
+func parseTCPOptional(optionalFields []string, rule *chainRule) (consumed int, err error) {
+	for _, value := range optionalFields {
+		if !strings.ContainsRune(value, ':') {
+			// no longer a TCP-associated option
+			return consumed, nil
+		}
+		switch {
+		case strings.HasPrefix(value, "dpt:"):
+			rule.destinationPort, err = parseDestinationPort(value)
+			if err != nil {
+				return 0, fmt.Errorf("parsing destination port: %w", err)
+			}
+			consumed++
+		case strings.HasPrefix(value, "spt:"):
+			rule.sourcePort, err = parseSourcePort(value)
+			if err != nil {
+				return 0, fmt.Errorf("parsing source port: %w", err)
+			}
+			consumed++
+		case strings.HasPrefix(value, "flags:"):
+			rule.tcpFlags, err = parseTCPFlags(value)
+			if err != nil {
+				return 0, fmt.Errorf("parsing TCP flags: %w", err)
+			}
+			consumed++
+		default:
+			return 0, fmt.Errorf("%w: %s", errTCPOptionalUnknown, value)
+		}
+	}
+	return consumed, nil
+}
+
+func parseDestinationPort(value string) (port uint16, err error) {
+	value = strings.TrimPrefix(value, "dpt:")
+	return parsePort(value)
+}
+
+func parseSourcePort(value string) (port uint16, err error) {
+	value = strings.TrimPrefix(value, "spt:")
+	return parsePort(value)
+}
+
+var errTCPFlagsMalformed = errors.New("TCP flags are malformed")
+
+func parseTCPFlags(value string) (tcpFlags, error) {
+	value = strings.TrimPrefix(value, "flags:")
+	fields := strings.Split(value, "/")
+	const expectedFields = 2
+	if len(fields) != expectedFields {
+		return tcpFlags{}, fmt.Errorf("%w: expected format 'flags:<mask>/<comparison>' in %q",
+			errTCPFlagsMalformed, value)
+	}
+	maskFlags := strings.Split(fields[0], ",")
+	mask := make([]tcpFlag, len(maskFlags))
+	var err error
+	for i, maskFlag := range maskFlags {
+		mask[i], err = parseTCPFlag(maskFlag)
+		if err != nil {
+			return tcpFlags{}, fmt.Errorf("parsing TCP mask flags: %w", err)
+		}
+	}
+	comparisonFlags := strings.Split(fields[1], ",")
+	comparison := make([]tcpFlag, len(comparisonFlags))
+	for i, comparisonFlag := range comparisonFlags {
+		comparison[i], err = parseTCPFlag(comparisonFlag)
+		if err != nil {
+			return tcpFlags{}, fmt.Errorf("parsing TCP comparison flags: %w", err)
+		}
+	}
+	return tcpFlags{
+		mask:       mask,
+		comparison: comparison,
+	}, nil
+}
+
 func parsePortsCSV(s string) (ports []uint16, err error) {
 	if s == "" {
 		return nil, nil
@@ -286,16 +414,40 @@ func parsePortsCSV(s string) (ports []uint16, err error) {
 	fields := strings.Split(s, ",")
 	ports = make([]uint16, len(fields))
 	for i, field := range fields {
-		const base, bitLength = 10, 16
-		port, err := strconv.ParseUint(field, base, bitLength)
+		ports[i], err = parsePort(field)
 		if err != nil {
-			return nil, fmt.Errorf("parsing port %q: %w", field, err)
+			return nil, err
 		}
-		ports[i] = uint16(port)
 	}
 	return ports, nil
 }
 
+var errMarkValueMalformed = errors.New("mark value is malformed")
+
+func parseMark(optionalFields []string) (m mark, consumed int, err error) {
+	switch optionalFields[consumed] {
+	case "match":
+		consumed++
+		if optionalFields[consumed] == "!" {
+			m.invert = true
+			consumed++
+		}
+
+		const base = 0 // auto-detect
+		const bits = 32
+		value, err := strconv.ParseUint(optionalFields[consumed], base, bits)
+		if err != nil {
+			return mark{}, 0, fmt.Errorf("%w: %s", errMarkValueMalformed, optionalFields[consumed])
+		}
+		m.value = uint(value)
+		consumed++
+	default:
+		return mark{}, 0, fmt.Errorf("%w: unexpected mark mode field: %s",
+			ErrChainRuleMalformed, optionalFields[consumed])
+	}
+	return m, consumed, nil
+}
+
 var ErrLineNumberIsZero = errors.New("line number is zero")
 
 func parseLineNumber(s string) (n uint16, err error) {
@@ -323,12 +475,12 @@ var ErrProtocolUnknown = errors.New("unknown protocol")
 
 func parseProtocol(s string) (protocol string, err error) {
 	switch s {
-	case "0":
-	case "1":
+	case "0", "all":
+	case "1", "icmp":
 		protocol = "icmp"
-	case "6":
+	case "6", "tcp":
 		protocol = "tcp"
-	case "17":
+	case "17", "udp":
 		protocol = "udp"
 	default:
 		return "", fmt.Errorf("%w: %s", ErrProtocolUnknown, s)

internal/firewall/iptables/list_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"net/netip"
@@ -58,6 +58,7 @@ num pkts bytes target     prot opt in     out     source               destinati
 2   0     0 ACCEPT     6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:55405
 3   0     0 ACCEPT     1    --  tun0   *       0.0.0.0/0            0.0.0.0/0
 4   0     0 DROP       0    --  tun0   *       1.2.3.4              0.0.0.0/0
+5   0     0 ACCEPT     all  --  tun0   *       1.2.3.4              0.0.0.0/0
 `,
 			table: chain{
 				name:    "INPUT",
@@ -111,6 +112,17 @@ num pkts bytes target     prot opt in     out     source               destinati
 						source:          netip.MustParsePrefix("1.2.3.4/32"),
 						destination:     netip.MustParsePrefix("0.0.0.0/0"),
 					},
+					{
+						lineNumber:      5,
+						packets:         0,
+						bytes:           0,
+						target:          "ACCEPT",
+						protocol:        "",
+						inputInterface:  "tun0",
+						outputInterface: "*",
+						source:          netip.MustParsePrefix("1.2.3.4/32"),
+						destination:     netip.MustParsePrefix("0.0.0.0/0"),
+					},
 				},
 			},
 		},

internal/firewall/iptables/mocks_generate_test.go

@@ -1,3 +1,3 @@
-package firewall
+package iptables
 
 //go:generate mockgen -destination=mocks_test.go -package $GOPACKAGE . CmdRunner,Logger

internal/firewall/iptables/mocks_test.go

@@ -1,8 +1,8 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/qdm12/gluetun/internal/firewall (interfaces: CmdRunner,Logger)
+// Source: github.com/qdm12/gluetun/internal/firewall/iptables (interfaces: CmdRunner,Logger)
 
-// Package firewall is a generated GoMock package.
-package firewall
+// Package iptables is a generated GoMock package.
+package iptables
 
 import (
 	exec "os/exec"

internal/firewall/iptables/parse.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"errors"
@@ -18,10 +18,13 @@ type iptablesInstruction struct {
 	inputInterface  string       // for example "tun0" or "" for any interface.
 	outputInterface string       // for example "tun0" or "" for any interface.
 	source          netip.Prefix // if not valid, then it is unspecified.
+	sourcePort      uint16       // if zero, there is no source port
 	destination     netip.Prefix // if not valid, then it is unspecified.
 	destinationPort uint16       // if zero, there is no destination port
 	toPorts         []uint16     // if empty, there is no redirection
 	ctstate         []string     // if empty, there is no ctstate
+	tcpFlags        tcpFlags
+	mark            mark
 }
 
 func (i *iptablesInstruction) setDefaults() {
@@ -43,6 +46,8 @@ func (i *iptablesInstruction) equalToRule(table, chain string, rule chainRule) (
 		return false
 	case i.destinationPort != rule.destinationPort:
 		return false
+	case i.sourcePort != rule.sourcePort:
+		return false
 	case !slices.Equal(i.toPorts, rule.redirPorts):
 		return false
 	case !slices.Equal(i.ctstate, rule.ctstate):
@@ -55,6 +60,11 @@ func (i *iptablesInstruction) equalToRule(table, chain string, rule chainRule) (
 		return false
 	case !ipPrefixesEqual(i.destination, rule.destination):
 		return false
+	case !slices.Equal(i.tcpFlags.mask, rule.tcpFlags.mask) ||
+		!slices.Equal(i.tcpFlags.comparison, rule.tcpFlags.comparison):
+		return false
+	case i.mark != rule.mark:
+		return false
 	default:
 		return true
 	}
@@ -77,26 +87,29 @@ func parseIptablesInstruction(s string) (instruction iptablesInstruction, err er
 		return iptablesInstruction{}, fmt.Errorf("%w: empty instruction", ErrIptablesCommandMalformed)
 	}
 	fields := strings.Fields(s)
-	if len(fields)%2 != 0 {
-		return iptablesInstruction{}, fmt.Errorf("%w: fields count %d is not even: %q",
-			ErrIptablesCommandMalformed, len(fields), s)
-	}
 
-	for i := 0; i < len(fields); i += 2 {
-		key := fields[i]
-		value := fields[i+1]
-		err = parseInstructionFlag(key, value, &instruction)
+	i := 0
+	for i < len(fields) {
+		consumed, err := parseInstructionFlag(fields[i:], &instruction)
 		if err != nil {
 			return iptablesInstruction{}, fmt.Errorf("parsing %q: %w", s, err)
 		}
+		i += consumed
 	}
 
 	instruction.setDefaults()
 	return instruction, nil
 }
 
-func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (err error) {
-	switch key {
+func parseInstructionFlag(fields []string, instruction *iptablesInstruction) (consumed int, err error) {
+	consumed, err = preCheckInstructionFields(fields)
+	if err != nil {
+		return 0, err
+	}
+	flag := fields[0]
+	value := fields[1]
+
+	switch flag {
 	case "-t", "--table":
 		instruction.table = value
 	case "-D", "--delete":
@@ -109,7 +122,19 @@ func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (
 		instruction.target = value
 	case "-p", "--protocol":
 		instruction.protocol = value
-	case "-m", "--match": // ignore match
+	case "-m", "--match":
+		consumed, err = parseMatchModule(fields, instruction)
+		if err != nil {
+			return 0, fmt.Errorf("parsing match module: %w", err)
+		}
+	case "--mark":
+		const base = 0 // auto-detect
+		const bits = 32
+		value, err := strconv.ParseUint(value, base, bits)
+		if err != nil {
+			return 0, fmt.Errorf("parsing mark value %q: %w", fields[2], err)
+		}
+		instruction.mark.value = uint(value)
 	case "-i", "--in-interface":
 		instruction.inputInterface = value
 	case "-o", "--out-interface":
@@ -117,37 +142,61 @@ func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (
 	case "-s", "--source":
 		instruction.source, err = parseIPPrefix(value)
 		if err != nil {
-			return fmt.Errorf("parsing source IP CIDR: %w", err)
+			return 0, fmt.Errorf("parsing source IP CIDR: %w", err)
+		}
+	case "--sport":
+		instruction.sourcePort, err = parsePort(value)
+		if err != nil {
+			return 0, fmt.Errorf("parsing source port: %w", err)
 		}
 	case "-d", "--destination":
 		instruction.destination, err = parseIPPrefix(value)
 		if err != nil {
-			return fmt.Errorf("parsing destination IP CIDR: %w", err)
+			return 0, fmt.Errorf("parsing destination IP CIDR: %w", err)
 		}
 	case "--dport":
-		const base, bitLength = 10, 16
-		destinationPort, err := strconv.ParseUint(value, base, bitLength)
+		instruction.destinationPort, err = parsePort(value)
 		if err != nil {
-			return fmt.Errorf("parsing destination port: %w", err)
+			return 0, fmt.Errorf("parsing destination port: %w", err)
 		}
-		instruction.destinationPort = uint16(destinationPort)
 	case "--ctstate":
 		instruction.ctstate = strings.Split(value, ",")
 	case "--to-ports":
-		portStrings := strings.Split(value, ",")
-		instruction.toPorts = make([]uint16, len(portStrings))
-		for i, portString := range portStrings {
-			const base, bitLength = 10, 16
-			port, err := strconv.ParseUint(portString, base, bitLength)
-			if err != nil {
-				return fmt.Errorf("parsing port redirection: %w", err)
-			}
-			instruction.toPorts[i] = uint16(port)
+		instruction.toPorts, err = parseToPorts(value)
+		if err != nil {
+			return 0, fmt.Errorf("parsing port redirection: %w", err)
+		}
+	case "--tcp-flags":
+		mask, comparison := value, fields[2]
+		instruction.tcpFlags, err = parseTCPFlags(mask + "/" + comparison)
+		if err != nil {
+			return 0, fmt.Errorf("parsing TCP flags: %w", err)
 		}
 	default:
-		return fmt.Errorf("%w: unknown key %q", ErrIptablesCommandMalformed, key)
+		return 0, fmt.Errorf("%w: unknown key %q", ErrIptablesCommandMalformed, flag)
+	}
+	return consumed, nil
+}
+
+func preCheckInstructionFields(fields []string) (consumed int, err error) {
+	flag := fields[0]
+	// All flags use one value after the flag, except the following:
+	switch flag {
+	case "--tcp-flags": // -m can have 1 or 2 values
+		const expected = 3
+		if len(fields) < expected {
+			return 0, fmt.Errorf("%w: flag %q requires at least 2 values, but got %s",
+				ErrIptablesCommandMalformed, flag, strings.Join(fields, " "))
+		}
+		return expected, nil
+	default:
+		const expected = 2
+		if len(fields) < expected {
+			return 0, fmt.Errorf("%w: flag %q requires a value, but got none",
+				ErrIptablesCommandMalformed, flag)
+		}
+		return expected, nil
 	}
-	return nil
 }
 
 func parseIPPrefix(value string) (prefix netip.Prefix, err error) {
@@ -162,3 +211,52 @@ func parseIPPrefix(value string) (prefix netip.Prefix, err error) {
 	}
 	return netip.PrefixFrom(ip, ip.BitLen()), nil
 }
+
+func parsePort(value string) (port uint16, err error) {
+	const base, bitLength = 10, 16
+	portValue, err := strconv.ParseUint(value, base, bitLength)
+	if err != nil {
+		return 0, err
+	}
+	return uint16(portValue), nil
+}
+
+func parseMatchModule(fields []string, instruction *iptablesInstruction) (
+	consumed int, err error,
+) {
+	_ = fields[consumed] // -m or --match flag already detected
+	consumed++
+	switch fields[consumed] {
+	case "tcp", "udp":
+		consumed++
+		// for now ignore the protocol match since it's auto-loaded
+		// when parsing the -p/--protocol flag, and we don't need to
+		// parse it twice.
+	case "mark":
+		consumed++
+		switch fields[consumed] {
+		case "!":
+			consumed++
+			instruction.mark.invert = true
+		default:
+			return consumed, fmt.Errorf("%w: unsupported match mark with value: %s",
+				ErrIptablesCommandMalformed, fields[2])
+		}
+	default:
+		return 0, fmt.Errorf("%w: unknown match value: %s",
+			ErrIptablesCommandMalformed, fields[consumed])
+	}
+	return consumed, nil
+}
+
+func parseToPorts(value string) (toPorts []uint16, err error) {
+	portStrings := strings.Split(value, ",")
+	toPorts = make([]uint16, len(portStrings))
+	for i, portString := range portStrings {
+		toPorts[i], err = parsePort(portString)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return toPorts, nil
+}

internal/firewall/iptables/parse_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"net/netip"
@@ -23,7 +23,7 @@ func Test_parseIptablesInstruction(t *testing.T) {
 		"uneven_fields": {
 			s:          "-A",
 			errWrapped: ErrIptablesCommandMalformed,
-			errMessage: "iptables command is malformed: fields count 1 is not even: \"-A\"",
+			errMessage: "parsing \"-A\": iptables command is malformed: flag \"-A\" requires a value, but got none",
 		},
 		"unknown_key": {
 			s:          "-x something",

internal/firewall/iptables/support.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -11,10 +11,10 @@ import (
 )
 
 var (
-	ErrNetAdminMissing      = errors.New("NET_ADMIN capability is missing")
-	ErrTestRuleCleanup      = errors.New("failed cleaning up test rule")
-	ErrInputPolicyNotFound  = errors.New("input policy not found")
-	ErrIPTablesNotSupported = errors.New("no iptables supported found")
+	ErrNetAdminMissing     = errors.New("NET_ADMIN capability is missing")
+	ErrTestRuleCleanup     = errors.New("failed cleaning up test rule")
+	ErrInputPolicyNotFound = errors.New("input policy not found")
+	ErrNotSupported        = errors.New("no iptables supported found")
 )
 
 func checkIptablesSupport(ctx context.Context, runner CmdRunner,
@@ -57,7 +57,7 @@ func checkIptablesSupport(ctx context.Context, runner CmdRunner,
 	}
 
 	return "", fmt.Errorf("%w: errors encountered are: %s",
-		ErrIPTablesNotSupported, strings.Join(allUnsupportedMessages, "; "))
+		ErrNotSupported, strings.Join(allUnsupportedMessages, "; "))
 }
 
 func testIptablesPath(ctx context.Context, path string,

internal/firewall/iptables/support_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -101,7 +101,7 @@ func Test_checkIptablesSupport(t *testing.T) {
 				return runner
 			},
 			iptablesPathsToTry: []string{"path1", "path2"},
-			errSentinel:        ErrIPTablesNotSupported,
+			errSentinel:        ErrNotSupported,
 			errMessage: "no iptables supported found: " +
 				"errors encountered are: " +
 				"path1: output 1 (exit code 4); " +

internal/firewall/iptables/tcp.go

@@ -0,0 +1,96 @@
+package iptables
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/netip"
+)
+
+type tcpFlags struct {
+	mask       []tcpFlag
+	comparison []tcpFlag
+}
+
+type tcpFlag uint8
+
+const (
+	tcpFlagFIN tcpFlag = 1 << iota
+	tcpFlagSYN
+	tcpFlagRST
+	tcpFlagPSH
+	tcpFlagACK
+	tcpFlagURG
+	tcpFlagECE
+	tcpFlagCWR
+)
+
+func (f tcpFlag) String() string {
+	switch f {
+	case tcpFlagFIN:
+		return "FIN"
+	case tcpFlagSYN:
+		return "SYN"
+	case tcpFlagRST:
+		return "RST"
+	case tcpFlagPSH:
+		return "PSH"
+	case tcpFlagACK:
+		return "ACK"
+	case tcpFlagURG:
+		return "URG"
+	case tcpFlagECE:
+		return "ECE"
+	case tcpFlagCWR:
+		return "CWR"
+	default:
+		panic(fmt.Sprintf("%s: %d", errTCPFlagUnknown, f))
+	}
+}
+
+var errTCPFlagUnknown = errors.New("unknown TCP flag")
+
+func parseTCPFlag(s string) (tcpFlag, error) {
+	allFlags := []tcpFlag{
+		tcpFlagFIN, tcpFlagSYN, tcpFlagRST, tcpFlagPSH,
+		tcpFlagACK, tcpFlagURG, tcpFlagECE, tcpFlagCWR,
+	}
+	for _, flag := range allFlags {
+		if s == fmt.Sprintf("%#02x", uint8(flag)) || s == flag.String() {
+			return flag, nil
+		}
+	}
+	return 0, fmt.Errorf("%w: %s", errTCPFlagUnknown, s)
+}
+
+var ErrMarkMatchModuleMissing = errors.New("kernel is missing the mark module libxt_mark.so")
+
+// TempDropOutputTCPRST temporarily drops outgoing TCP RST packets to the specified address and port,
+// for any TCP packets not marked with the excludeMark given.
+// This is necessary for TCP path MTU discovery to work, as the kernel will try to terminate the connection
+// by sending a TCP RST packet, although we want to handle the connection manually.
+func (c *Config) TempDropOutputTCPRST(ctx context.Context,
+	src, dst netip.AddrPort, excludeMark int) (
+	revert func(ctx context.Context) error, err error,
+) {
+	if !c.nftables && !c.xtMark {
+		return nil, fmt.Errorf("%w", ErrMarkMatchModuleMissing)
+	}
+
+	const template = "%s OUTPUT -p tcp -s %s --sport %d -d %s --dport %d " +
+		"--tcp-flags RST RST -m mark ! --mark %d -j DROP" //nolint:dupword
+	instruction := fmt.Sprintf(template, "--append", src.Addr(), src.Port(), dst.Addr(), dst.Port(), excludeMark)
+	revertInstruction := fmt.Sprintf(template, "--delete", src.Addr(), src.Port(), dst.Addr(), dst.Port(), excludeMark)
+	run := c.runIptablesInstruction
+	if dst.Addr().Is6() {
+		run = c.runIP6tablesInstruction
+	}
+	revert = func(ctx context.Context) error {
+		return run(ctx, revertInstruction)
+	}
+	err = run(ctx, instruction)
+	if err != nil {
+		return nil, fmt.Errorf("running instruction: %w", err)
+	}
+	return revert, nil
+}

internal/firewall/iptablesmix.go

@@ -1,21 +0,0 @@
-package firewall
-
-import (
-	"context"
-)
-
-func (c *Config) runMixedIptablesInstructions(ctx context.Context, instructions []string) error {
-	for _, instruction := range instructions {
-		if err := c.runMixedIptablesInstruction(ctx, instruction); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (c *Config) runMixedIptablesInstruction(ctx context.Context, instruction string) error {
-	if err := c.runIptablesInstruction(ctx, instruction); err != nil {
-		return err
-	}
-	return c.runIP6tablesInstruction(ctx, instruction)
-}

internal/firewall/nftables/atomic.go

@@ -0,0 +1,99 @@
+package nftables
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/nftables"
+)
+
+// SaveAndRestore saves the current nftables tree and returns a restore function that
+// can be called to restore the saved tree.
+func (f *Firewall) SaveAndRestore(_ context.Context) (restore func(context.Context), err error) {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return nil, fmt.Errorf("creating nftables connection: %w", err)
+	}
+	tables, err := saveTables(conn)
+	if err != nil {
+		return nil, fmt.Errorf("saving nftables state: %w", err)
+	}
+	return func(_ context.Context) {
+		conn, err := nftables.New()
+		if err != nil {
+			f.logger.Warnf("creating nftables connection for restore: %s", err)
+			return
+		}
+		err = restoreTables(conn, tables)
+		if err != nil {
+			f.logger.Warnf("restoring nftables state: %s", err)
+		}
+	}, nil
+}
+
+type savedTable struct {
+	table  *nftables.Table
+	chains []savedChain
+}
+
+type savedChain struct {
+	chain *nftables.Chain
+	rules []*nftables.Rule
+}
+
+func saveTables(conn *nftables.Conn) ([]savedTable, error) {
+	tables, err := conn.ListTables()
+	if err != nil {
+		return nil, err
+	}
+
+	savedTables := make([]savedTable, len(tables))
+	for i, table := range tables {
+		savedTables[i].table = table
+
+		chains, err := conn.ListChains()
+		if err != nil {
+			return nil, err
+		}
+
+		for _, chain := range chains {
+			if chain.Table.Name != table.Name ||
+				chain.Table.Family != table.Family {
+				continue
+			}
+			rules, err := conn.GetRules(table, chain)
+			if err != nil {
+				return nil, fmt.Errorf("getting rules for chain %s in table %s: %w", chain.Name, table.Name, err)
+			}
+			savedChain := savedChain{chain: chain, rules: rules}
+			savedTables[i].chains = append(savedTables[i].chains, savedChain)
+		}
+	}
+
+	return savedTables, nil
+}
+
+func restoreTables(conn *nftables.Conn, savedTables []savedTable) error {
+	conn.FlushRuleset()
+
+	for _, savedTable := range savedTables {
+		table := conn.AddTable(savedTable.table)
+		for _, savedChain := range savedTable.chains {
+			// Make the [nftables.Chain.Table] points to the new [nftables.Table]
+			// created in this connection.
+			savedChain.chain.Table = table
+			savedChain.chain = conn.AddChain(savedChain.chain)
+
+			for _, rule := range savedChain.rules {
+				rule.Table = table
+				rule.Chain = savedChain.chain
+				conn.AddRule(rule)
+			}
+		}
+	}
+
+	return conn.Flush()
+}

internal/firewall/nftables/basechains.go

@@ -0,0 +1,50 @@
+package nftables
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/google/nftables"
+)
+
+var ErrPolicyUnknown = errors.New("unknown policy")
+
+// SetBaseChainsPolicy sets the policy of all the base chains (INPUT, FORWARD, or OUTPUT)
+// for the filter table to the given policy (accept or drop).
+func (f *Firewall) SetBaseChainsPolicy(_ context.Context, policy string) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	var chainPolicy nftables.ChainPolicy
+	switch strings.ToLower(policy) {
+	case "accept":
+		chainPolicy = nftables.ChainPolicyAccept
+	case "drop":
+		chainPolicy = nftables.ChainPolicyDrop
+	default:
+		return fmt.Errorf("%w: %s", ErrPolicyUnknown, policy)
+	}
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	_, inputChain, forwardChain, outputChain := setupFilterWithBaseChains(conn)
+	inputChain.Policy = &chainPolicy
+	forwardChain.Policy = &chainPolicy
+	outputChain.Policy = &chainPolicy
+
+	conn.AddChain(inputChain)
+	conn.AddChain(forwardChain)
+	conn.AddChain(outputChain)
+
+	err = conn.Flush()
+	if err != nil {
+		return fmt.Errorf("flushing nftables changes: %w", err)
+	}
+
+	return nil
+}

internal/firewall/nftables/conntrack.go

@@ -0,0 +1,61 @@
+package nftables
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+)
+
+func (f *Firewall) AcceptEstablishedRelatedTraffic(_ context.Context) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	table, inputChain, _, outputChain := setupFilterWithBaseChains(conn)
+
+	ctStateExprs := []expr.Any{
+		&expr.Ct{
+			Key:      expr.CtKeySTATE,
+			Register: 1,
+		},
+		&expr.Bitwise{
+			SourceRegister: 1,
+			DestRegister:   1,
+			Len:            4, //nolint:mnd
+			Mask:           []byte{byte(expr.CtStateBitESTABLISHED | expr.CtStateBitRELATED), 0x00, 0x00, 0x00},
+			Xor:            []byte{0x00, 0x00, 0x00, 0x00},
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpNeq,
+			Register: 1,
+			Data:     []byte{0x00, 0x00, 0x00, 0x00},
+		},
+		&expr.Verdict{
+			Kind: expr.VerdictAccept,
+		},
+	}
+
+	conn.AddRule(&nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: ctStateExprs,
+	})
+
+	conn.AddRule(&nftables.Rule{
+		Table: table,
+		Chain: outputChain,
+		Exprs: ctStateExprs,
+	})
+
+	if err := conn.Flush(); err != nil {
+		return fmt.Errorf("flushing: %w", err)
+	}
+
+	return nil
+}

internal/firewall/nftables/delete.go

@@ -0,0 +1,27 @@
+package nftables
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"github.com/google/nftables"
+)
+
+var errRuleToDeleteNotFound = errors.New("rule not found for removal")
+
+func (f *Firewall) deleteRule(conn *nftables.Conn, rule *nftables.Rule) error {
+	for i, existing := range f.rules {
+		if !reflect.DeepEqual(existing, rule) {
+			continue
+		}
+		err := conn.DelRule(existing)
+		if err != nil {
+			return fmt.Errorf("deleting rule: %w", err)
+		}
+		f.rules[i], f.rules[len(f.rules)-1] = f.rules[len(f.rules)-1], f.rules[i]
+		f.rules = f.rules[:len(f.rules)-1]
+		return nil
+	}
+	return fmt.Errorf("%w: %#v", errRuleToDeleteNotFound, rule)
+}

internal/firewall/nftables/filter.go

@@ -0,0 +1,38 @@
+package nftables
+
+import "github.com/google/nftables"
+
+func setupFilterWithBaseChains(conn *nftables.Conn) (table *nftables.Table,
+	inputChain, forwardChain, outputChain *nftables.Chain,
+) {
+	table = conn.AddTable(&nftables.Table{
+		Family: nftables.TableFamilyINet,
+		Name:   "filter",
+	})
+
+	inputChain = conn.AddChain(&nftables.Chain{
+		Name:     "input",
+		Table:    table,
+		Type:     nftables.ChainTypeFilter,
+		Hooknum:  nftables.ChainHookInput,
+		Priority: nftables.ChainPriorityFilter,
+	})
+
+	forwardChain = conn.AddChain(&nftables.Chain{
+		Name:     "forward",
+		Table:    table,
+		Type:     nftables.ChainTypeFilter,
+		Hooknum:  nftables.ChainHookForward,
+		Priority: nftables.ChainPriorityFilter,
+	})
+
+	outputChain = conn.AddChain(&nftables.Chain{
+		Name:     "output",
+		Table:    table,
+		Type:     nftables.ChainTypeFilter,
+		Hooknum:  nftables.ChainHookOutput,
+		Priority: nftables.ChainPriorityFilter,
+	})
+
+	return table, inputChain, forwardChain, outputChain
+}

internal/firewall/nftables/firewall.go

@@ -0,0 +1,22 @@
+package nftables
+
+import (
+	"sync"
+
+	"github.com/google/nftables"
+)
+
+type Firewall struct {
+	logger Logger
+
+	// rules are only rules added and tracked for later removal.
+	// Not all rules added are tracked for removal.
+	rules []*nftables.Rule
+	mutex sync.Mutex
+}
+
+func New(logger Logger) *Firewall {
+	return &Firewall{
+		logger: logger,
+	}
+}

internal/firewall/nftables/input.go

@@ -0,0 +1,170 @@
+package nftables
+
+import (
+	"context"
+	"fmt"
+	"net/netip"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+)
+
+func (f *Firewall) AcceptInputThroughInterface(_ context.Context, intf string) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	table, inputChain, _, _ := setupFilterWithBaseChains(conn)
+
+	rule := &nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: []expr.Any{
+			&expr.Meta{
+				Key:      expr.MetaKeyIIFNAME,
+				Register: 1,
+			},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     []byte(intf + "\x00"),
+			},
+			&expr.Verdict{
+				Kind: expr.VerdictAccept,
+			},
+		},
+	}
+
+	conn.AddRule(rule)
+
+	err = conn.Flush()
+	if err != nil {
+		return fmt.Errorf("flushing: %w", err)
+	}
+
+	return nil
+}
+
+// AcceptInputToPort accepts incoming traffic on the specified port, for both TCP and UDP
+// protocols, on the interface intf. If intf is empty or "*", the interface is not used as a filter.
+// If remove is true, the rule is removed instead of added. This is used for port forwarding, with
+// intf set to the VPN tunnel interface.
+func (f *Firewall) AcceptInputToPort(_ context.Context, intf string, port uint16, remove bool) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	table, inputChain, _, _ := setupFilterWithBaseChains(conn)
+	portBytes := []byte{byte(port >> 8), byte(port)} //nolint:mnd
+	const tcp, udp uint8 = 6, 17
+	protocols := []uint8{tcp, udp}
+
+	for _, protocol := range protocols {
+		const maxExprsLen = 7
+		exprs := make([]expr.Any, 0, maxExprsLen)
+		if intf != "" && intf != "*" {
+			exprs = append(exprs,
+				&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+				&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
+			)
+		}
+		exprs = append(exprs,
+			&expr.Payload{DestRegister: 1, Base: expr.PayloadBaseNetworkHeader, Offset: 9, Len: 1}, //nolint:mnd
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte{protocol}},
+			&expr.Payload{DestRegister: 1, Base: expr.PayloadBaseTransportHeader, Offset: 2, Len: 2}, //nolint:mnd
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: portBytes},
+			&expr.Verdict{Kind: expr.VerdictAccept},
+		)
+
+		rule := &nftables.Rule{
+			Table: table,
+			Chain: inputChain,
+			Exprs: exprs,
+		}
+
+		if !remove {
+			conn.AddRule(rule)
+			f.rules = append(f.rules, rule)
+			continue
+		}
+		err = f.deleteRule(conn, rule)
+		if err != nil {
+			return fmt.Errorf("deleting rule: %w", err)
+		}
+	}
+
+	err = conn.Flush()
+	if err != nil {
+		f.rules = f.rules[:len(f.rules)-len(protocols)]
+		return fmt.Errorf("flushing: %w", err)
+	}
+
+	return nil
+}
+
+func (f *Firewall) AcceptInputToSubnet(_ context.Context, intf string, subnet netip.Prefix) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	table, inputChain, _, _ := setupFilterWithBaseChains(conn)
+
+	const maxExprsLen = 5
+	exprs := make([]expr.Any, 0, maxExprsLen)
+
+	if intf != "" && intf != "*" {
+		exprs = append(exprs,
+			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
+		)
+	}
+
+	var payloadOffset uint32
+	if subnet.Addr().Is4() {
+		payloadOffset = 16
+	} else {
+		payloadOffset = 24
+	}
+
+	exprs = append(exprs,
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       payloadOffset,
+			Len:          uint32(len(subnet.Addr().AsSlice())), //nolint:gosec
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     subnet.Addr().AsSlice(),
+		},
+		&expr.Verdict{Kind: expr.VerdictAccept},
+	)
+
+	rule := &nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: exprs,
+	}
+
+	conn.AddRule(rule)
+
+	err = conn.Flush()
+	if err != nil {
+		return fmt.Errorf("flushing: %w", err)
+	}
+
+	return nil
+}

internal/firewall/nftables/interfaces.go

@@ -0,0 +1,5 @@
+package nftables
+
+type Logger interface {
+	Warnf(format string, args ...any)
+}

internal/firewall/nftables/output.go

@@ -0,0 +1,78 @@
+package nftables
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+)
+
+func (f *Firewall) AcceptIpv6MulticastOutput(_ context.Context, intf string) error {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	conn, err := nftables.New()
+	if err != nil {
+		return fmt.Errorf("creating nftables connection: %w", err)
+	}
+
+	table, _, _, outputChain := setupFilterWithBaseChains(conn)
+
+	const maxExprsLen = 6
+	exprs := make([]expr.Any, 0, maxExprsLen)
+
+	if intf != "" && intf != "*" {
+		exprs = append(exprs,
+			&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
+		)
+	}
+
+	// ff02::1:ff00:0/104 mask is 13 bytes of 0xff
+	mask := []byte{
+		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00,
+	} //nolint:mnd
+	addr := []byte{
+		0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x01, 0xff, 0x00, 0x00, 0x00,
+	} //nolint:mnd
+
+	exprs = append(exprs,
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       24, // IPv6 Destination Address offset //nolint:mnd
+			Len:          16, //nolint:mnd
+		},
+		&expr.Bitwise{
+			SourceRegister: 1,
+			DestRegister:   1,
+			Len:            16, //nolint:mnd
+			Mask:           mask,
+			Xor:            []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, //nolint:mnd
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     addr,
+		},
+		&expr.Verdict{Kind: expr.VerdictAccept},
+	)
+
+	rule := &nftables.Rule{
+		Table: table,
+		Chain: outputChain,
+		Exprs: exprs,
+	}
+
+	conn.AddRule(rule)
+
+	err = conn.Flush()
+	if err != nil {
+		return fmt.Errorf("flushing: %w", err)
+	}
+
+	return nil
+}

internal/firewall/nftables/support.go

@@ -0,0 +1,12 @@
+package nftables
+
+import "github.com/google/nftables"
+
+func IsSupported() bool {
+	conn, err := nftables.New()
+	if err != nil {
+		return false
+	}
+	_, err = conn.ListTable("filter")
+	return err == nil
+}

internal/firewall/outboundsubnets.go

@@ -48,7 +48,7 @@ func (c *Config) removeOutboundSubnets(ctx context.Context, subnets []netip.Pref
 			}
 
 			firewallUpdated = true
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subNet, remove)
 			if err != nil {
 				c.logger.Error("cannot remove outdated outbound subnet: " + err.Error())
@@ -77,7 +77,7 @@ func (c *Config) addOutboundSubnets(ctx context.Context, subnets []netip.Prefix)
 			}
 
 			firewallUpdated = true
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subnet, remove)
 			if err != nil {
 				return err

internal/firewall/ports.go

@@ -35,7 +35,7 @@ func (c *Config) SetAllowedPort(ctx context.Context, port uint16, intf string) (
 	c.logger.Info("setting allowed input port " + fmt.Sprint(port) + " through interface " + intf + "...")
 
 	const remove = false
-	if err := c.acceptInputToPort(ctx, intf, port, remove); err != nil {
+	if err := c.impl.AcceptInputToPort(ctx, intf, port, remove); err != nil {
 		return fmt.Errorf("allowing input to port %d through interface %s: %w",
 			port, intf, err)
 	}
@@ -68,7 +68,7 @@ func (c *Config) RemoveAllowedPort(ctx context.Context, port uint16) (err error)
 
 	const remove = true
 	for netInterface := range interfacesSet {
-		err := c.acceptInputToPort(ctx, netInterface, port, remove)
+		err := c.impl.AcceptInputToPort(ctx, netInterface, port, remove)
 		if err != nil {
 			return fmt.Errorf("removing allowed port %d on interface %s: %w",
 				port, netInterface, err)

internal/firewall/redirect.go

@@ -50,7 +50,7 @@ func (c *Config) RedirectPort(ctx context.Context, intf string, sourcePort,
 		return nil
 	case conflict != nil:
 		const remove = true
-		err = c.redirectPort(ctx, conflict.interfaceName, conflict.sourcePort,
+		err = c.impl.RedirectPort(ctx, conflict.interfaceName, conflict.sourcePort,
 			conflict.destinationPort, remove)
 		if err != nil {
 			return fmt.Errorf("removing conflicting redirection: %w", err)
@@ -60,7 +60,7 @@ func (c *Config) RedirectPort(ctx context.Context, intf string, sourcePort,
 	}
 
 	const remove = false
-	err = c.redirectPort(ctx, intf, sourcePort, destinationPort, remove)
+	err = c.impl.RedirectPort(ctx, intf, sourcePort, destinationPort, remove)
 	if err != nil {
 		return fmt.Errorf("redirecting port: %w", err)
 	}

internal/firewall/vpn.go

@@ -28,7 +28,7 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	remove := true
 	if c.vpnConnection.IP.IsValid() {
 		for _, defaultRoute := range c.defaultRoutes {
-			if err := c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove); err != nil {
+			if err := c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove); err != nil {
 				c.logger.Error("cannot remove outdated VPN connection rule: " + err.Error())
 			}
 		}
@@ -36,7 +36,7 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	c.vpnConnection = models.Connection{}
 
 	if c.vpnIntf != "" {
-		if err = c.acceptOutputThroughInterface(ctx, c.vpnIntf, remove); err != nil {
+		if err = c.impl.AcceptOutputThroughInterface(ctx, c.vpnIntf, remove); err != nil {
 			c.logger.Error("cannot remove outdated VPN interface rule: " + err.Error())
 		}
 	}
@@ -45,13 +45,13 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	remove = false
 
 	for _, defaultRoute := range c.defaultRoutes {
-		if err := c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, connection, remove); err != nil {
+		if err := c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, connection, remove); err != nil {
 			return fmt.Errorf("allowing output traffic through VPN connection: %w", err)
 		}
 	}
 	c.vpnConnection = connection
 
-	if err = c.acceptOutputThroughInterface(ctx, vpnIntf, remove); err != nil {
+	if err = c.impl.AcceptOutputThroughInterface(ctx, vpnIntf, remove); err != nil {
 		return fmt.Errorf("accepting output traffic through interface %s: %w", vpnIntf, err)
 	}
 	c.vpnIntf = vpnIntf

internal/firewall/wrappers.go

@@ -0,0 +1,21 @@
+package firewall
+
+import (
+	"context"
+	"net/netip"
+)
+
+func (c *Config) Version(ctx context.Context) (version string, err error) {
+	return c.impl.Version(ctx)
+}
+
+// TempDropOutputTCPRST temporarily drops outgoing TCP RST packets to the specified address and port,
+// for any TCP packets not marked with the excludeMark given.
+// This is necessary for TCP path MTU discovery to work, as the kernel will try to terminate the connection
+// by sending a TCP RST packet, although we want to handle the connection manually.
+func (c *Config) TempDropOutputTCPRST(ctx context.Context,
+	src, dst netip.AddrPort, excludeMark int) (
+	revert func(ctx context.Context) error, err error,
+) {
+	return c.impl.TempDropOutputTCPRST(ctx, src, dst, excludeMark)
+}

internal/healthcheck/checker.go

@@ -0,0 +1,362 @@
+package healthcheck
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"net/netip"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/qdm12/gluetun/internal/healthcheck/dns"
+	"github.com/qdm12/gluetun/internal/healthcheck/icmp"
+)
+
+type Checker struct {
+	tlsDialAddrs   []string
+	dialer         *net.Dialer
+	echoer         *icmp.Echoer
+	dnsClient      *dns.Client
+	logger         Logger
+	icmpTargetIPs  []netip.Addr
+	smallCheckType string
+	startupOnFail  bool
+	configMutex    sync.Mutex
+
+	icmpNotPermitted *bool
+
+	// Internal periodic service signals
+	stop context.CancelFunc
+	done <-chan struct{}
+}
+
+func NewChecker(logger Logger) *Checker {
+	return &Checker{
+		dialer: &net.Dialer{
+			Resolver: &net.Resolver{
+				PreferGo: true,
+			},
+		},
+		echoer:    icmp.NewEchoer(logger),
+		dnsClient: dns.New(),
+		logger:    logger,
+	}
+}
+
+// SetConfig sets the following:
+// - TCP+TLS dial addresses
+// - ICMP echo IP addresses to target
+// - the desired small check type (dns or icmp)
+// - whether to startup the periodic checks if the startup check fails.
+// This function MUST be called before calling [Checker.Start].
+func (c *Checker) SetConfig(tlsDialAddrs []string, icmpTargets []netip.Addr,
+	smallCheckType string, startupOnFail bool,
+) {
+	c.configMutex.Lock()
+	defer c.configMutex.Unlock()
+	c.tlsDialAddrs = tlsDialAddrs
+	c.icmpTargetIPs = icmpTargets
+	c.smallCheckType = smallCheckType
+	c.startupOnFail = startupOnFail
+}
+
+// Start starts the [Checker] which behaves differently according to its
+// internal field startupOnFail, which is set by calling [Checker.SetConfig].
+//
+// By default, startupOnFail should be false and the behavior is as follows:
+// A blocking 6s-timed TCP+TLS check is performed first. If it fails,
+// an error is returned and the [Checker] is not started.
+// On success, it starts the periodic checks in a separate goroutine, returning
+// the runError error channel and a nil error.
+//
+// If startupOnFail is true, the behavior is as follows:
+// A blocking 6s-timed TCP+TLS check is performed first. If it fails,
+// the error is sent to the runError channel, but no error is returned
+// and the [Checker] continues to start the periodic checks in a separate goroutine, returning
+// the runError error channel and a nil error.
+//
+// The periodic checks consist in:
+// - a "small" ICMP echo check every minute
+// - a "full" TCP+TLS check every 5 minutes
+//
+// The [Checker] has to be ultimately stopped by calling [Checker.Stop].
+func (c *Checker) Start(ctx context.Context) (runError <-chan error, err error) {
+	if len(c.tlsDialAddrs) == 0 || len(c.icmpTargetIPs) == 0 || c.smallCheckType == "" {
+		panic("call Checker.SetConfig with non empty values before Checker.Start")
+	}
+
+	if c.icmpNotPermitted != nil && *c.icmpNotPermitted {
+		// restore forced check type to dns if icmp was found to be not permitted
+		c.smallCheckType = smallCheckDNS
+	}
+	c.echoer.Reset()
+
+	// runErrorCh MUST be buffered in the case startupOnFail is true, and
+	// a startup error was encountered, to avoid blocking the startup
+	// goroutine when sending the error, especially since the caller may
+	// not be ready to receive from the channel yet.
+	runErrorCh := make(chan error, 1)
+	runError = runErrorCh
+	err = c.startupCheck(ctx)
+	if err != nil {
+		err = fmt.Errorf("startup check: %w", err)
+		if !c.startupOnFail {
+			return nil, err
+		}
+		runErrorCh <- err
+	}
+
+	ready := make(chan struct{})
+	ctx, cancel := context.WithCancel(context.Background())
+	c.stop = cancel
+	done := make(chan struct{})
+	c.done = done
+	const smallCheckPeriod = time.Minute
+	smallCheckTimer := time.NewTimer(smallCheckPeriod)
+	const fullCheckPeriod = 5 * time.Minute
+	fullCheckTimer := time.NewTimer(fullCheckPeriod)
+	go func() {
+		defer close(done)
+		close(ready)
+		for {
+			select {
+			case <-ctx.Done():
+				fullCheckTimer.Stop()
+				smallCheckTimer.Stop()
+				return
+			case <-smallCheckTimer.C:
+				err := c.smallPeriodicCheck(ctx)
+				if err != nil {
+					err = fmt.Errorf("small periodic check: %w", err)
+				}
+				select {
+				case <-ctx.Done():
+					continue
+				case runErrorCh <- err:
+				}
+				smallCheckTimer.Reset(smallCheckPeriod)
+			case <-fullCheckTimer.C:
+				err := c.fullPeriodicCheck(ctx)
+				if err != nil {
+					err = fmt.Errorf("full periodic check: %w", err)
+				}
+				select {
+				case <-ctx.Done():
+					continue
+				case runErrorCh <- err:
+				}
+				fullCheckTimer.Reset(fullCheckPeriod)
+			}
+		}
+	}()
+	<-ready
+	return runError, nil
+}
+
+func (c *Checker) Stop() error {
+	c.stop()
+	<-c.done
+	c.tlsDialAddrs = nil
+	c.icmpTargetIPs = nil
+	c.smallCheckType = ""
+	return nil
+}
+
+func (c *Checker) smallPeriodicCheck(ctx context.Context) error {
+	c.configMutex.Lock()
+	icmpTargetIPs := make([]netip.Addr, len(c.icmpTargetIPs))
+	copy(icmpTargetIPs, c.icmpTargetIPs)
+	c.configMutex.Unlock()
+	tryTimeouts := []time.Duration{
+		5 * time.Second,
+		5 * time.Second,
+		5 * time.Second,
+		10 * time.Second,
+		10 * time.Second,
+		10 * time.Second,
+		15 * time.Second,
+		15 * time.Second,
+		15 * time.Second,
+		30 * time.Second,
+	}
+	check := func(ctx context.Context, try int) error {
+		if c.smallCheckType == smallCheckDNS {
+			return c.dnsClient.Check(ctx)
+		}
+		ip := icmpTargetIPs[try%len(icmpTargetIPs)]
+		err := c.echoer.Echo(ctx, ip)
+		if c.icmpNotPermitted == nil && errors.Is(err, icmp.ErrNotPermitted) {
+			c.icmpNotPermitted = new(bool)
+			*c.icmpNotPermitted = true
+			c.smallCheckType = smallCheckDNS
+			c.logger.Infof("%s; permanently falling back to %s checks",
+				err, smallCheckTypeToString(c.smallCheckType))
+			return c.dnsClient.Check(ctx)
+		}
+		return err
+	}
+	return withRetries(ctx, tryTimeouts, c.logger, smallCheckTypeToString(c.smallCheckType), check)
+}
+
+func (c *Checker) fullPeriodicCheck(ctx context.Context) error {
+	// 20s timeout in case the connection is under stress
+	// See https://github.com/qdm12/gluetun/issues/2270
+	tryTimeouts := []time.Duration{10 * time.Second, 15 * time.Second, 30 * time.Second}
+	check := func(ctx context.Context, try int) error {
+		tlsDialAddr := c.tlsDialAddrs[try%len(c.tlsDialAddrs)]
+		return tcpTLSCheck(ctx, c.dialer, tlsDialAddr)
+	}
+	return withRetries(ctx, tryTimeouts, c.logger, "TCP+TLS dial", check)
+}
+
+func tcpTLSCheck(ctx context.Context, dialer *net.Dialer, targetAddress string) error {
+	// TODO use mullvad API if current provider is Mullvad
+
+	address, err := makeAddressToDial(targetAddress)
+	if err != nil {
+		return err
+	}
+
+	const dialNetwork = "tcp4"
+	connection, err := dialer.DialContext(ctx, dialNetwork, address)
+	if err != nil {
+		return fmt.Errorf("dialing: %w", err)
+	}
+
+	if strings.HasSuffix(address, ":443") {
+		host, _, err := net.SplitHostPort(address)
+		if err != nil {
+			return fmt.Errorf("splitting host and port: %w", err)
+		}
+		tlsConfig := &tls.Config{
+			MinVersion: tls.VersionTLS12,
+			ServerName: host,
+		}
+		tlsConnection := tls.Client(connection, tlsConfig)
+		err = tlsConnection.HandshakeContext(ctx)
+		if err != nil {
+			return fmt.Errorf("running TLS handshake: %w", err)
+		}
+	}
+
+	err = connection.Close()
+	if err != nil {
+		return fmt.Errorf("closing connection: %w", err)
+	}
+
+	return nil
+}
+
+func makeAddressToDial(address string) (addressToDial string, err error) {
+	host, port, err := net.SplitHostPort(address)
+	if err != nil {
+		addrErr := new(net.AddrError)
+		ok := errors.As(err, &addrErr)
+		if !ok || addrErr.Err != "missing port in address" {
+			return "", fmt.Errorf("splitting host and port from address: %w", err)
+		}
+		host = address
+		const defaultPort = "443"
+		port = defaultPort
+	}
+	address = net.JoinHostPort(host, port)
+	return address, nil
+}
+
+var ErrAllCheckTriesFailed = errors.New("all check tries failed")
+
+func withRetries(ctx context.Context, tryTimeouts []time.Duration,
+	logger Logger, checkName string, check func(ctx context.Context, try int) error,
+) error {
+	maxTries := len(tryTimeouts)
+	type errData struct {
+		err        error
+		durationMS int64
+	}
+	errs := make([]errData, maxTries)
+	for i, timeout := range tryTimeouts {
+		start := time.Now()
+		checkCtx, cancel := context.WithTimeout(ctx, timeout)
+		err := check(checkCtx, i)
+		cancel()
+		switch {
+		case err == nil:
+			return nil
+		case ctx.Err() != nil:
+			return fmt.Errorf("%s: %w", checkName, ctx.Err())
+		}
+		logger.Debugf("%s attempt %d/%d failed: %s", checkName, i+1, maxTries, err)
+		errs[i].err = err
+		errs[i].durationMS = time.Since(start).Round(time.Millisecond).Milliseconds()
+	}
+
+	errStrings := make([]string, len(errs))
+	for i, err := range errs {
+		errStrings[i] = fmt.Sprintf("attempt %d (%dms): %s", i+1, err.durationMS, err.err)
+	}
+	return fmt.Errorf("%w:\n\t%s", ErrAllCheckTriesFailed, strings.Join(errStrings, "\n\t"))
+}
+
+func (c *Checker) startupCheck(ctx context.Context) error {
+	// connection isn't under load yet when the checker starts, so a short
+	// 6 seconds timeout suffices and provides quick enough feedback that
+	// the new connection is not working. However, since the addresses to dial
+	// may be multiple, we run the check in parallel. If any succeeds, the check passes.
+	// This is to prevent false negatives at startup, if one of the addresses is down
+	// for external reasons.
+	const timeout = 6 * time.Second
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+	errCh := make(chan error)
+
+	for _, address := range c.tlsDialAddrs {
+		go func(addr string) {
+			err := tcpTLSCheck(ctx, c.dialer, addr)
+			errCh <- err
+		}(address)
+	}
+
+	errs := make([]error, 0, len(c.tlsDialAddrs))
+	success := false
+	for range c.tlsDialAddrs {
+		err := <-errCh
+		if err == nil {
+			success = true
+			cancel()
+			continue
+		} else if success {
+			continue // ignore canceled errors after success
+		}
+
+		c.logger.Debugf("startup check parallel attempt failed: %s", err)
+		errs = append(errs, err)
+	}
+	if success {
+		return nil
+	}
+
+	errStrings := make([]string, len(errs))
+	for i, err := range errs {
+		errStrings[i] = fmt.Sprintf("parallel attempt %d/%d failed: %s", i+1, len(errs), err)
+	}
+	return fmt.Errorf("%w: %s", ErrAllCheckTriesFailed, strings.Join(errStrings, ", "))
+}
+
+const (
+	smallCheckDNS  = "dns"
+	smallCheckICMP = "icmp"
+)
+
+func smallCheckTypeToString(smallCheckType string) string {
+	switch smallCheckType {
+	case smallCheckICMP:
+		return "ICMP echo"
+	case smallCheckDNS:
+		return "plain DNS over UDP"
+	default:
+		panic("unknown small check type: " + smallCheckType)
+	}
+}