I've always wanted to know how to enable routing and NAT on XP box without enabling ICS (Internet Connection Sharing). Today it's time to write some lines about it. Let's begin.
1. We should enable service "Routing and Remote Access"
2. Open registry editor and navigate to "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" and set IPEnableRouter to "1"
Then, open a command prompt and type the following commands:
3. netsh routing ip nat install
4. netsh routing ip nat add interface "WAN Interface Name" full
5. netsh routing ip nat add interface "LAN Interface Name" private
I'm not sure whether computer has to be restarted after this setup, but the answer is probably "yes".
Anyway, if something doesn't agree to work - just restart the computer before panic :D
P.S. One more thing to add:
To check configured interfaces type netsh routing ip nat show interface
