problems getting server on line

[RAY]

Greetings;
I have an existing server running FreeBsd 6.3. It's running as a name/web/mail 
server. 
I have built a new server to replace it running FreeBsd 7.0. I have both 
servers attached to the same router, with the production server sitting in 
the DMZ. I have tried to switch them over by simply changing which server the 
DMZ points to. When I did this, the new server didn't work. I could connect 
to the webserver  (telnet to port 80) using either localhost or the private 
IP address (192.168...), but not using the domain name. I could connect to 
the default website properly from another computer on the same router using 
the private ip address.
My first guess was that it was the firewall on the server configured 
incorrectly, so I disabled PF which didn't help.

Any suggestions would be very much appreciated.
Ray