- Remove `DNS_SERVER` (aka DOT) option: the DNS server forwarder part is now always enabled (see below why)
- Remove `DNS_KEEP_NAMESERVER`: the container will always use the built-in DNS server forwarder, because it can handle now local names with local resolvers (see #2970), it can use the `plain` upstream type (see https://github.com/qdm12/gluetun/commit/5ed6e8292278b54bb5081de0e8ccd0d63a275b3c) AND you can use `DNS_UPSTREAM_PLAIN_ADDRESSES` (see below)
- Replace `DNS_ADDRESS` with `DNS_UPSTREAM_PLAIN_ADDRESSES`:
- New CSV format with port, for example `ip1:port1,ip2:port2`
- requires `DNS_UPSTREAM_TYPE=plain` to be set to use `DNS_UPSTREAM_PLAIN_ADDRESSES` (unless using retro `DNS_ADDRESS`)
- retrocompatibility with `DNS_ADDRESS`. If set, force upstream type to plain and empty user-picked providers. 127.0.0.1 is now ignored since it's always set to this value internally.
- Warning log on using private upstream resolvers updated
- Warning log if using a private IP address for the plain DNS server which is not in your local subnets
All in all, this greatly simplifies code and available options (less options for the same features is a win). It also allows you to specify multiple plain DNS resolvers on ports other than 53 if needed.
- Migrate `DOT` to `DNS_SERVER`
- Migrate `DOT_PROVIDERS` to `DNS_UPSTREAM_RESOLVERS`
- Migrate `DOT_PRIVATE_ADDRESS` to `DNS_PRIVATE_ADDRESSES`
- Migrate `DOT_CACHING` to `DNS_CACHING`
- Migrate `DOT_IPV6` to `DNS_UPSTREAM_IPV6`
- Better settings tree structure logged using `qdm12/gotree`
- Read settings from environment variables, then files, then secret files
- Settings methods to default them, merge them and override them
- `DNS_PLAINTEXT_ADDRESS` default changed to `127.0.0.1` to use DoT. Warning added if set to something else.
- `HTTPPROXY_LISTENING_ADDRESS` instead of `HTTPPROXY_PORT` (with retro-compatibility)
Quentin McGaw