[Pdns-users] CNAME answer problem?

bert hubert bert.hubert at netherlabs.nl
Fri Aug 10 08:30:49 UTC 2007

On Fri, Aug 10, 2007 at 07:34:51AM +0200, Hannes M. wrote:
> i have some strange problem with CNAME records to an external domain.
> For example:

This is a commonly observed oddity of the domain name system.

Indeed, powerdns returns a 'servfail' if you ask it for www3.example.com,
but it turns out that resolving nameservers ('recursors') know about that.

The reason powerdns needs to return servfail is because it cannot faithfully
answer the question - it does not know about 'www.somewhere-else.com', that
domain is 'out of its bailiwick' in DNS speak.

However, recursors get the hint and continue resolving for

So what you observe is the 'SERVFAIL', because you did not configure
powerdns to resolve for you.

If you'd include a line 'recursor=' for example, you would get a
complete answer, because in that case powerdns would offload the processing
of www.somewhere-else.com to the configured recursor.

For www.example.com this won't work as it is a fake domain, but you get the

> dig +norecurs www3.example.com delivers the CNAME as stored, but PDNS
> does not resolve.

Well, that is as it should be.

Good luck!

http://www.PowerDNS.com      Open source, database driven DNS Software 
http://netherlabs.nl              Open and Closed source services

More information about the Pdns-users mailing list