[Dnsmasq-discuss] dnsmasq and VPN client updates resolv.conf with multiple nameservers

[Geert Stappers]

On Thu, Nov 04, 2021 at 10:00:03AM +0100, Johannes Stezenbach wrote:
> On Thu, Nov 04, 2021 at 07:46:18AM +0100, Geert Stappers via Dnsmasq-discuss wrote:
> > On Wed, Nov 03, 2021 at 11:45:15PM +0100, Johannes Stezenbach wrote:
> > > 
> > > I've tried current git version v2.87test4-2-g9560658c5ba2.
> > > 
> > > Usually /run/dnsmasq/resolv.conf has only one entry for my
> > > home Wifi router.
> > > When I enable a VPN connection two more entries are added,
> > > but dnsmasq doesn't read it correctly.
> > 
> > } but dnsmasq doesn't deal with it as I expected.
> > or
> > } but dnsmasq doesn't deal with it as I hoped for.
> 
> It is a regression compared to cbbd56c96583, which I used before
> because it had the fix for an issue I had reported.
> 
> > > Real:
> > > nameserver 10.x.xx.60
> > > nameserver 10.x.xx.75
> > > nameserver 192.168.178.1
> > >
> > > dnsmasq log:
> > > Nov  3 23:19:56 dnsmasq[31323]: reading /run/dnsmasq/resolv.conf
> > > Nov  3 23:19:56 dnsmasq[31323]: using nameserver 192.168.178.1#53
> > > Nov  3 23:19:56 dnsmasq[31323]: using nameserver 10.x.xx.75#53
> > > Nov  3 23:19:56 dnsmasq[31323]: using nameserver 192.168.178.1#53
> 
> > > FWIW I still use --strict-order.
>  
> I suppose --strict-order could play a role here.
 
Yes could be, but with
>>> Real:
>>> nameserver 10.x.xx.60
>>> nameserver 10.x.xx.75
>>> nameserver 192.168.178.1

there should have be
>>> dnsmasq log:
>>> Nov  3 23:19:56 dnsmasq[31323]: reading /run/dnsmasq/resolv.conf
}}} Nov  3 23:19:56 dnsmasq[31323]: using nameserver 10.x.xx.60#53
>>> Nov  3 23:19:56 dnsmasq[31323]: using nameserver 10.x.xx.75#53
>>> Nov  3 23:19:56 dnsmasq[31323]: using nameserver 192.168.178.1#53


> } My guess it that reloading  dnsmasq after VPN open / close could help.
> > Please expriment with it and report back.
> 
> On restart dnsmasq reads it correctly. Sorry I neglected to
> clearly desribe this problem only happens when dnsmasq
> re-reads the /run/dnsmasq/resolv.conf after it changed.
> I tried SIGHUP but it doesn't work to re-read the file.
> "touch /run/dnsmasq/resolv.conf" causes dnsmasq to
> re-read it again, but with same result.
> 

Acknowledge on "reporting a regresssion".

IIRC is it the first report about it.


Advice:
Tell how to reproduce the inconvenience.


Another advice, more a challenge: `git bisect`

<screenshot>
stappers at paddy:~/src/dnsmasq
$ git bisect start
stappers at paddy:~/src/dnsmasq
$ git bisect bad 9560658c5ba2
stappers at paddy:~/src/dnsmasq
$ git bisect good cbbd56c96583
Bisecting: 8 revisions left to test after this (roughly 3 steps)
[d2ad5dc073aaacaf22b117f16106282a73586803] Fix truncation logic in make_local_answer()
stappers at paddy:~/src/dnsmasq
$ 
</screenshot>


Groeten
Geert Stappers
-- 
Silence is hard to parse