We got a few computers (less than 10) in 2 subnets. We have one Windows XP computer with 2 LAN adapters. We want to use this computer as a very simple router in the middle of the two subnets.

In NT 4 we can simply open the properties of TCP/IP and check “Enable IP Routing”. However, in Windows XP we don’t have this checkbox in TCP/IP properties. To make the same effect, we need to change something in the registry.

Click “Start”, click “run” and enter “regedit”.

Locate “HKEY_LOCAL_MACHINESystemCurrentControlSetServicesTcpipParameters”, we can find a value called “IPEnableRouter”. Let’s double click it and set the value to “1”. We are all set then.

This is not good for large enterprises. But for some specific very small businesses enabling Windows XP as the simple router will save the cost, as we don’t need to buy a new copy of Windows Server 2003 only for the Routing feature.