dnsproxy: invalid answer where there are no DNS servers available

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


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


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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