[Dnsmasq-discuss] dnsmasq & SERVFAIL

[Simon Kelley]

István Váradi wrote:

> A few days ago, my ISP's primary name server had some problem, and
> returned SERVFAIL for most queries. dnsmasq simply forwarded this
> message to clients without trying the secondary name server (which 
> worked well). Is it a bug or is it normal behaviour? If it is normal behaviour, 
> would it be possible for dnsmasq to try the other name servers in this
> case (at least as option)?
> 

It's not quite that simple (dnsmasq can't try the other nameservers 
itself, since it doesn't keep a copy of the query once it has been 
forwarded, only just enough information to return the answer.)

It would however be possible to tweak the code so that (i) a SERVFAIL 
reply triggers the "look for a good server to use" code and (ii) a 
server returning SERVFAIL repsonses is not counted as a good server. 
That would have  the effect of turning the problem you saw into a 
transient one, instead of always failing, one or two queries might fail, 
bu then dnsmasq would move to the secondary server.

I'll add that to the next release. Thanks for the suggestion.

Cheers,

Simon.