I haven’t posted anything about Linux in quite a while (half-finished posts on upgrading to FC3 and then to FC4 never made it out the door), but I’ve recently upgraded my laptop and desktop to Fedora Core 5. For the most part, things have gone quite well.

The one major exception would be networking. I just installed a 400 GB drive in the desktop, and then decided that I should upgrade to FC5 at the same time. I started to regret that decision when my network connection would stay up for only about a minute after booting. If I disconnected and reconnected the Ethernet cable, it would work again for a minute or so.

Fortunately, my wife and I had dinner tonight with a friend of ours who was in from Sydney for work meetings at Cisco. Knowing that he was far more knowledgeable about networks and Linux than I, I pumped him for info. After I mentioned that the Tulip driver was being used, he suggested that I add that to my search keywords. He also suggested that it sounded like the desktop was having trouble getting an IP address from the DHCP server. He was right on both accounts. Genius!

After a bit of searching, I turned up a series of forum posts that saved the day – this one in particular (Wrong driver loaded for Davicom ethernet card). It turns out that the Tulip driver probably should have never been used with the Davicom ethernet card, though it had worked with older Linux kernels. Apparently a change sometime around the 2.6.15 kernel sealed the incompatibility. You can fix the problem by following the directions in the page linked to above to force the kernel to use the dmfe driver instead of the tulip driver.

Unfortunately, until the problem is fixed upstream in the kernel, you have to reapply these changes every time you upgrade to a new kernel.