Internet lockup

[Gordon Gallup]

Greetings All,
   Sorry if this appears twice, but an earlier message got lost in cyberspace.
   I have a new e-machine T6420.  It is connected to a hub with three
other machines and the hub is connected to a Siemans DSL
"modem-router".  I installed FC5 on the T6420.  FC5 is configured to
use DHCP at boot time. The behavior is somewhat flakey, but it appears
that ssh and sftp (particularly the
latter) break networking if I attempt to send too much information.
It appears to require a reboot to re-estaablish contact. Fiddling with
the inetd.network script does nothing I can detect, although it thinks
the network is up.  Before the death, pinging works fine all around
the machines connected to the hub and also to my office machine across
town.  In addition, Firefox works for a while, but I can't say yet
just how long.
   Attempting to connect with the kio-slave 'fish' never works.
Thanks for any help, GAG