dnsproxy: invalid answer where there are no DNS servers available

Nuno Gonçalves nunojpg at gmail.com
Sun Jul 7 10:02:45 PDT 2019


Hi,

I did hacked this to work for me, and it will take some substantial
work to upstream. Anyway I hope I can do it soon.

I do have a question on this subsystem, when compiling with
--with-dns-backend=systemd-resolved (instead of internal), what is the
intended behaviour for tether clients?

Currently I think they get no DNS server.

Should we send them the systemd-revolved upstream server?

Should dnsproxy be split into the proxy part and the caching part,
where the proxy will continue to be used to relay requests to
systemd-resolved?

Thanks,
Nuno

On Mon, Apr 1, 2019 at 8:29 AM Daniel Wagner <wagi at monom.org> wrote:
>
> Hi Nuno,
>
> On 3/28/19 2:40 PM, Nuno Gonçalves wrote:
> > Hi,
> >
> > Typing "ping abcd", where abcd does not exist on /etc/hosts or in the
> > search domains, will usually hang for a while with Connman.
> >
> > I've compared with other systems and my conclusion is that libnss_dns
> > is retrying the DNS request to connman, since connman answer does not
> > include the query field.
> >
> > This behaviour comes from [1], where both a invalid Query and no
> > upstream servers are handled in the same way.
> >
> > I believe the query field must be part of the answer when the Query
> > message was valid, but just happens to not be possible to resolve.
>
> Thanks for you report. Do you happen to have a patch for this? I suppose
> you have the setup already running for testing.
>
> Thanks,
> Daniel


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