Re: dnsmasq default configuration changed

[Petr Menšík]

Please, Stephen, would you please read what I wrote, not what Kevin 
wrongly deducted?

The change I made in dnsmasq does not conflict with systemd-resolved in 
default configuration or if configured correctly. I have wrote scenario, 
when it can conflict and how to fix it. So no, there is no need to 
revert my change. If it is, *PLEASE* report it with exact step to 
reproduce. I have tested those changes do not cause regressions. If you 
(or anyone else) know something I have missed, I need much more precise 
steps than those below to fix it.

I would suggest everyone to try that change in rawhide actually, verify 
what is listening on and whether it does conflict with anything. I use 
"lsof -np $(pidof dnsmasq)" command for quick checks.

On 15. 01. 24 20:04, Stephen Gallagher wrote:
>  On Mon, Jan 15, 2024 at 11:32 AM Kevin Kofler via devel
>  <devel(a)lists.fedoraproject.org&gt;  wrote:
> > Petr Menšík wrote:
> >> systemd-resolved is unfortunately known to broken.
> > [snip]
> >> Dnsmasq does not break DNSSEC, systemd-resolved does.
> > [snip]
> >> Unfortunately broken are clients having systemd-resolved enabled.
> > How exactly is it broken? If you refer to:
> > https://github.com/systemd/systemd/issues/25676
> > fixes for that are finally coming in now (as of 3 weeks ago). 
I have reported issues known to me:

https://github.com/systemd/systemd/issues?q=is%3Aopen+is%3Aissue+author%3...

https://bugzilla.redhat.com/buglist.cgi?quicksearch=reporter%3Apemensik%4...

There are some others, which I consider important enough. If it works 
for you, good for you. It does not work well for others, I do not want 
to discuss it here. This thread is about dnsmasq only and I would like 
to focus to that only.

> >
> >> I would recommend having systemd-resolved forwarded to dnsmasq, which can
> >> then be forwarded further.
> > If you think dnsmasq should replace systemd-resolved by default, then please
> > propose that through the Changes process, which will also ensure the glibc
> > resolver, NetworkManager, and the like get configured properly for it.
> > Simply shipping dnsmasq with a default configuration that conflicts with
> > systemd-resolved is not a productive approach.
> >
> > If systemd-resolved is really broken, then it either needs to be fixed or
> > replaced. The former needs to be handled through systemd upstream, the
> > latter through the Fedora Changes process. 
Yes, I plan to propose changes to
default system wide resolver, because 
long reported bugs to systemd-resolved were mostly ignored. For years. 
But the solution I want to propose is not replacing it with dnsmasq. I 
am dnsmasq maintainer, I know it has own issues. In my opinion it is 
less broken, but not perfect. We are preparing different solution, which 
should be better. But it is not yet ready and therefore there is no 
Fedora Change filled. We fill create that once we are sure it brings 
features without causing regressions.
> >
> >> But this change should create conflict with systemd-resolved only in case
> >> it was improperly configured.
> > But the default configuration you ship will conflict.
> >
> >> Anyway, dnsmasq will listen by default on 127.0.0.1,
> >>   as every standard
> >> resolver does. You can use listen-address=127.0.0.53 if you like, but
> >> then it will conflict with systemd-resolved.
> > You just wrote that you make it listen by default on all interfaces, and
> > then filter. This means it will conflict over the port 53. That said,
> > listening on the lo interface only will also conflict with systemd-resolved
> > or any other local resolver, so you are probably right that your change does
> > not change much for the default configuration, it just makes it harder (more
> > settings to change) to set up coexistence. 127.0.0.53 is unfortunately not
> > an independent interface, it is still the lo interface.
> >
>  Based on my reading of this thread, this change is going to break the
>  default configuration and needs to be reverted immediately. Petr,
>  please file a Change Proposal for Fedora *41*. You have missed the
>  deadline for F40 System-Wide Changes (Dec. 26th) and this is
>  absolutely NOT a self-contained Change. 
I am sorry my intention were not understood correctly. Miroslav already 
mentioned that.We will fill System-Wide Change, but this change does not 
need it. If it breaks something, please use bug #2258062 to report 
details or create a new one for rawhide. But reproducible details are 
needed, not just assumptions.

Cheers,

Petr

PS: I consider it rude to be commented on issue closed for discussion, 
especially if the comment is misleading and false.

-- 
Petr Menšík
Software Engineer, RHEL
Red Hat,http://www.redhat.com/
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB