I had a new Ethernet card installed in my machine, because the old one didn't seem to be working. I'm now thinking that the problem may have something to do with a system update.

Here's my problem: I can get an Internet connection if, after booting the machine, I log in as root, enter
# ifdown eth1
# ifup eth1

But this only works when I have a hard connection to a T1 line. When I try to use these commands with my wireless network, the system complains that I don't have a cable connected.

Before, the machine booted up and found an address on it's own. I'd like to get back to that place. Any help would be appreciated.

Did you set things with network manager?

No, I didn't use Network Manager. But, as I said, the Ethernet card worked after a fashion with a direct T1 connection. The problem I'm having is that it will not work on my wireless LAN that connects to the machine using an Ethernet cable from a remote receiver.