As the title says.

System specs:

Pentium MMX 233
Intel 430TX
3C509 ISA ethernet card

The ethernet card works great in DOS, using IPX or TCP/IP protocols. Also works fine in Windows 95.

In Windows 3.1, I installed using the Ethernet IPX shim driver, which is the only way I was able to get it to work. This is how I usually set up my laptops as well, and it works everywhere else I've tried it. The built in 3C509 drivers do not work no matter what I do. I've tried every conceivable permutation of settings to try to make it work. FWIW, I have never been able to get those drivers to work on any machine with a 3C509.

In this situation, it will work fine for a while, but then it will disconnect for no apparent reason after a few minutes, rendering it unusable. Running ipconfig /renew fails. I have to restart Windows to make it work again (don't have to restart the whole computer).

I have no idea why this would happen. Anyone have any ideas?