Bug#1101975: systemd-resolved: resolved no longer resolves mdns, despite being configured to

[Herbert Snorrason]

On fim, apr 03 2025, Helmut Grohne wrote:
> The alternative of changing the default at compile time was the method
> preferred by the Debian Technical Committee, but that was not acceptable
> by the systemd maintainers.
Huh. Wouldn't that cause anyone relying on the default setting to run into the
same problem? Or does that cause the default config file to change significantly
enough to show up during an upgrade? The only reason I explicitly enabled mDNS
is because I figured I might as well remove the comment character when disabling
LLMNR.

It's maybe worth noting that it appears the comments in the default
resolved.conf are out of sync with reality. Most relevant here, they explicitly
say that deleting the conf file and drop-ins under /etc/ will restore the
defaults (which appear in the file), which is flatly incorrect when there are
drop-ins present in /usr. Should I suggest changing that to upstream?

> I agree that the disablement deserves a NEWS fragment. Do you use
> apt-listchanges to display such NEWS? Would that have made you aware of
> the problem? Would adding a note to Debian's release notes help here?
I believe so. That's installed by default, isn't it? I have made configuration
changes due to those messages before (and ignored a lot more) over the years, so
I suspect that would have helped.

With greetings,
  Herbert Snorrason