trouble accessing internet resources

[jv2351it]

My Redhat AS 3.0 Kernel 2.4.21-32.0.1 System has a problem. Most
websites I can access just fine, ex http://www.ibm.com 
but others I cannot
ex: http://www3.software.ibm.com or http://www.mozilla.org

Further, wget "http://www.mozilla.org/index.html" will eventually get
the file, but it takes ages.

This system has 2 NICs, one to the cable modem and the other to the
internal network.

Other PCs on the network (Windows) can access all sites no problem.

Started ethereal. Start mozilla, http://www3.software.ibm.com

Only traffic I see is:
tons of arpanet traffic,
lots of traffic from and to 127.0.0.1, may be related to CUPS,
DNS packets to get the IP, which returns the correct IP,
DNS packets to get the IP of www.rhns.redhat.com
https communication, looks like to Redhat, 

but no packets to http://www3.software.ibm.com

If I go to a working URL through a different Mozilla session, I see the
TCP and HTTP packets.

Any thoughts anyone?