Question : how to replace a network card?

Hi all

The LAN card in my ClearOS 6.9 server/gateway has died. I can still access it through the WAN port.

So I've dug out an old LAN card from my box of bits, tossed it (gently) into an old desktop, installed 6.9 and yes, that card works and is recognised.

Now I want to put it in my server to get the LAN interface back. I imagine it will need some sort of configuration change and that's beyond my linux skill set. I have the old computer with the card working, so I can at least copy something - if I know what to copy, that is.

Can anyone suggest how to go about this?

Thanks in advance.