DSL dies - eth1 dies?

["Chris Weiss" <cweiss stickyc com>]

I'm using Red Hat 6.1 to do IP routing using IPchains. One eth1 is plugged
into an Alcatel DSL modem and eth0 goes to a hub that serves 6 or so
Winboxes. If I temporarily lose the DSL connection (for isntance, by power
cycling the modem or by some mysterious upstream error), the connection is
never restored from linux. I'm unable to ping the gateway that's upstream.

eth0 is a Netgear 100base-T card.
eth1 is an Intel 10/100.

I can ping the other machines connected to eth0 and I can ping eth1 itself.
Pinging the gateway via ip (or any other sites) upstream of eth1 results in
a "destination host unreachable" error.
Bringing down eth1 and bringing it back up again (ifconfig eth1 down)does
not re-establish the connection.
Soft-rebooting (ctrl-alt-delete) does not restore the connection.
I'm forced to power cycle the machine and the modem to restore the
connection.
The PC is an Abit motherboard with first a Pentium 200mmx, then with an AMD
233.

Any thoughts on what could be causing this or where to start looking for
more troubleshooting info?
I'd hate to have to go back to WinNT and Sygate :(