SERVFAIL for some domains on some servers

[Stephane Bortzmeyer]

On Sat, Feb 27, 2010 at 06:51:44PM +0100,
 Oliver Henriot <Oliver.Henriot at imag.fr> wrote 
 a message of 104 lines which said:

> but my computing skills are scarce and I still have a lot to learn.

For instance, that you should always use real names 
<http://dougbarton.us/DNS/bind-users-FAQ.html#RealNames>

> - servers "2", "3" and "4" : slaves for my domain, recusrion allowed for  
> all, official resolvers for my clients, same configuration on all 3.  

Bad setup: you should really completely separate authoritative and
recursive services.

> Setup is DiG 9.3.6-P1 on CentOS 5.4.

That's a very old version.

> ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 37397

And the log?