When installing redhat, the 3c509 card is not detected. I have used netconf and linuxconf to configure the card via static and dhcp. The card does not initialize (delaying eth0 initializitian). There are 0 conflicts with the card and the address does not seem to matter. When I was able to force the init of the card prior to a reinstall, I could send packets out and not recieve any (even during dhcp). This seemed to be a problem in previous versions and there is no resolution listed. The card works just fine in Windows and I have tried PNP enabled and disabled.
Kernel issue?
This does not seem to be a kernel issue. The kernel is configured for network support out of the box and I have tried new kernels. Network and 3c509 support are enabled. There is no error message upon loading the driver, it finds the card no matter what address I put it on. I believe that the driver is bad and 3COM needs to create one that works.
The 3c509 driver works for everyone else I know of on the planet. Set the card to an IRQ, and I/O that are definitely free with the config program. Make sure that IRQ is marked as 'ISA/Legacy' in the BIOS and let me know if it helps After loading the module see what 'dmesg' says.
I've seen problems of a similiar nature on certain PCs. When using Micron PCs there is a BIOS bug in some models that will misallocate interrupts. The box is supposed to allocate PCI interrupts in a certain order. Knowing this order should allow the user to decide which interrupts are safe for use by ISA devices. Unfortunately sometimes the BIOS decides to allocate DIFFERENT interrupts for PCI usage thus leaving formerly working ISA gear not working. "It worked perfectly before, I have no idea what happened!" - sound familiar ? I'm not saying this is the problem in this case but I assure you this is a very real thing. The Microns I've seen this one use AMI BIOSes and I think it would be reasonable to wonder if other motherboards which use AMI BIOSes have the same or similiar problems. You might try catting /proc/pci and checking to see what it says about resource allocation.