dnsmasq sometimes lose primary dns (saucy)

[Franck]

Since I upgraded to Saucy, my local dnsmasq instance seems to lose its primary dns server and fallback to secondary dns.
Since the primary dns is a dnsmasq instance that knows of local servers, and the secondary one is external, my local dnsmasq instance fails to resolv local server names.

This does not happen on startup, it happens after some time. Restarting solves the issue.
It does not happen on Raring...

not sure where to look for to resolve this issue...

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: dnsmasq (not installed)
ProcVersionSignature: Ubuntu 3.11.0-8.15-generic 3.11.1
Uname: Linux 3.11.0-8-generic x86_64
ApportVersion: 2.12.4-0ubuntu1
Architecture: amd64
Date: Fri Sep 27 09:25:37 2013
InstallationDate: Installed on 2013-02-16 (222 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Alpha amd64 (20130216)
MarkForUpload: True
SourcePackage: dnsmasq
UpgradeStatus: Upgraded to saucy on 2013-09-19 (7 days ago)

[Simon Kelley (simon-thekelleys)]

On 27/09/13 10:37, Franck wrote:
> Public bug reported:
>
> Since I upgraded to Saucy, my local dnsmasq instance seems to lose its primary dns server and fallback to secondary dns.
> Since the primary dns is a dnsmasq instance that knows of local servers, and the secondary one is external, my local dnsmasq instance fails to resolv local server names.
>
> This does not happen on startup, it happens after some time. Restarting solves the issue.
> It does not happen on Raring...
>
> not sure where to look for to resolve this issue...
>

Dnsmasq doesn't consider the DNS servers to be "primary" and
"secondary". They're both equivalent, and which ever answers fastest
will be used. Every so often, the "race" is re-run, with a query sent to
all servers, and the one which answers first becoming the new preferred
server.

It's possible to change this behaviour to something more like what
you're expecting with the "strict-order" dnsmasq config flag. It's
possible that was set in Raring and is no longer in Saucy, or you might
just have been lucky before. Leaving it to the Ubuntu devs to answer that.

Cheers,

Simon.

[Franck (alci)]

Changing to network-manager, as it might be a nm-dnsmasq configuration issue (strict-order) (to be confirmed...)

[Franck (alci)]

Ok, nothing changed in the configuration, changed on my network instead. Sorry for the noise.

That said, some more insight doc on this subject (dns on Ubuntu) would be cool...

[Franck (alci)]

Was not a bug... but a tricky misconfiguration :-)

[Thomas Hood (jdthood)]

@Franck: See bug #1003842 for information about using dnsmasq with non-equivalent upstream nameservers.

[Franck (alci)]

@thomas: thanks for this indepth information. Discussion on bug #1003842 is indeed very enlightning!