How to trace cache information?

[Mark_Andrews at isc.org]

> Hi all,
> 
> We are seeing a problem when looking up information for the domain
> capacity.nl. Occasionally Named will return a NXDOMAIN for this domain,
> most of the time it works. The NXDOMAIN is cached for a while then. A
> database dump shows the following for capacity.nl when the lookup fails:
> 
> (This is under $ORIGIN nl.)
> 
> ;capacity       580     IN      A       NXDOMAIN        ;-$
> 
> (Further)
> $ORIGIN capacity.nl.
> mail    345580  IN      A       195.86.70.194   ;NT=134 Cr=addtnl
> 
> When the lookup is successful:
> 
> (Under $ORIGIN nl.)
> capacity        86356   IN      MX      100 mail.capacity.nl.   ;Cr=auth
>         86356   IN      MX      110 mx.wirehub.net.     ;Cr=auth
>         86356   IN      NS      mail.capacity.nl.       ;Cr=addtnl
>         86356   IN      NS      ns.wirehub.net. ;Cr=addtnl
>         86356   IN      NS      ns2.wirehub.net.        ;Cr=addtnl
> 
> (Further)
> $ORIGIN capacity.nl.
> mail    345556  IN      A       195.86.70.194   ;NT=193 Cr=addtnl
> Mastwijk        84839   IN      A       195.86.0.34     ;Cr=auth
> 
> I guess the NXDOMAIN result should have come from a server that is
> authoritive for the nl. zone. I have checked with dig, and all servers
> that are reported with "dig nl nx" have the correct information for
> capacity.nl. How can I find out where the NXDOMAIN result came from (which
> nameserver)? I have tried using debugging (kill -USR1 three times), but I
> was unable to deduce much from the named.run file. Some help here would be
> much appreciated.

	Add "host-statistics yes;" to named.conf.  The dump will then have
	the IP address of the machine that provided you with this answer.

	Mark
> 
> We are using Bind version 8.1 on FreeBSD 3.1-STABLE.
> 
> Thanks for your help.
> 
> Best regards,
> Edwin de Graaf
> -- 
> "O Oysters, come and walk with us!" The Walrus did beseech.
> 
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org