Problems resolving hosts

[Travis Troyer]

I am running FreeBSD 5.1 and I am suddenly having problems loading certain web 
pages.  The system is behind another FreeBSD machine acting as a router and 
DHCP server, so it pulls it's IP and such from the router machine.  I did not 
change any settings on either system, and suddenly some web sites have a 1-3 
minute delay in loading certain sites when using Mozilla, Netscape, or 
Konqueror.  I have tried booting into windows from the same system, and these 
same pages load in normal times.  They also load fine from any other machine 
on the network, so I am convinced it's a problem with this system's 
configuration, but I have no idea where to start.  I don't understand why 
most sites load fine, but a select handful won't.  I would appreciate it if 
anybody could share any ideas about this.  I can provide any configuration 
files or logs, if requested.

Thanks in advance,

Travis Troyer