- The order of NSS (host) modules has been brought in line with upstream
recommendations:
- The `myhostname` module is placed before the `resolve` (optional) and `dns`
entries, but after `file` (to allow overriding via `/etc/hosts` /
`networking.extraHosts`, and prevent ISPs with catchall-DNS resolvers from
hijacking `.localhost` domains)
- The `mymachines` module, which provides hostname resolution for local
containers (registered with `systemd-machined`) is placed to the front, to
make sure its mappings are preferred over other resolvers.
- If systemd-networkd is enabled, the `resolve` module is placed before
`files` and `myhostname`, as it provides the same logic internally, with
caching.
- The `mdns(_minimal)` module has been updated to the new priorities.
If you use your own NSS host modules, make sure to update your priorities
according to these rules:
- NSS modules which should be queried before `resolved` DNS resolution should
use mkBefore.
- NSS modules which should be queried after `resolved`, `files` and
`myhostname`, but before `dns` should use the default priority
- NSS modules which should come after `dns` should use mkAfter.