I had new connection to internet through external modem. We had a small office netwreok, then I connected to internet firstly using the old ethernet card. Now I bought and put the second one, now I can't configure the IP adresses etc. I want to share internet connection to lan through the server.
Who can help me?

You don't mention any OS or other specifications buddy? Please mention that what are you using?

We use just Windows XP sp2. Anything else I should mention?

Then you can use any proxy server software to share you internet on lan