[Resolvconf-devel] Bug#856015: may be dnsmasq issue

[Daniel Pocock]

I ran tcpdump on both the host and the OpenWRT router until another one
of these failures occurred.

The problem appears to be in the router, but as it is running dnsmasq as
well, just like resolvconf, resolvconf users could also be impacted by
the same issue depending on their configuration.

The router was sending the query to 5 different servers.  One of them is
not recursive and sends a response with the REFUSED error code.

If that is the first response dnsmasq receives, it sends a refused error
response back to the client.  It doesn't appear to wait for the other
responses or they didn't come quickly enough.

dnsmasq version on the router is 2.73-1

dnsmasq version on the Debian host is 2.72-3+deb8u1

stretch appears to have 2.76-5

Upstream changelog for 2.76-5 doesn't mention the issue.

Query sent on the dnsmasq mailing list

http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2017q1/011261.html