Question : Server 2003 DNS encountered an invalid domain name in a packet from ...

Our network has two Server 2003 DNS servers.  One of them has an error showing up in event viewer every seven seconds: "The DNS Server encountered an invalid domain name in a packet from x.x.x.x"  with one of four different IP addresses in each of the messages, most from 12.183.125.5.  I'm not very confident in the person who set up the DNS servers (who has since been fired) but I also don't have enough experience with them myself to know what to look for.   Neither of the servers have any Forwarders set.  Both are domain controllers and the one with the continuous errors is also our exchange server.  Looking for suggestions.  Thanks in advance.

Answer : Server 2003 DNS encountered an invalid domain name in a packet from ...

If it happens every seven seconds it might be worth while capturing a bit of network traffic with wireshark and see who originally sends which DNS query where.