BIND 9 Problem - DNS Forwarding

[Paul Howarth]

Kh Linux wrote:
> Dear all:
> 
> I had been running both BIND 8 and Squid under SuSe 6.2 until recently when
> I switched to RedHat 9 with BIND 9 and Squid from the 3 CDs.
> 
> Both in the old SuSe and new RedHat 9 now, I configure BIND to use
> forwarding by adding to /etc/named.conf this:
> 
>          forwarders {
>                 N.N.N.N; // The IP of ISP DNS Server
>         };
>         forward only;
> 
> 
> Now, BIND 9 always prints these errors below into /var/log/messages:
> 
> ---
> Oct 29 11:09:37 nslinux named[2787]: client 192.168.1.154#1264: updating
> zone 'my.office.org/IN': update failed: 'RRset exists (value dependent)'
> prerequisite not satisfied (NXRRSET)
> Oct 29 11:09:37 nslinux named[2787]: client 192.168.1.154#1267: update
> 'my.office.org/IN' denied
> ---

These messages are nothing to do with your forwarding. They are probably 
caused by being the DNS server for a domain that a bunch of Windows boxes are 
in. The Windows boxes are trying to do dynamic DNS updates when they get their 
DHCP leases.

See http://www.ibiblio.org/gferg/ldp/BIND+AD-HOWTO/BIND+AD-HOWTO.html for more 
info.

> And my 1 Mbps Internet connection (leased line) has always been saturated
> since the switch-over. I don't know if that is the DNS forwarding problem or
> a worm/spyware on my network.

You may need to use tcpdump/ethereal to see what the activity on the network is.

Paul.