This article tells how to make your windows XP (professional) machine work as a router by following simple steps.

There are situations in which we need to connect two different series network and make them communicate to each other. We need a router to make necessary routing of packets from one network to a different network. But for home router seems a costly option. However if you are having Windows XP professional you can make it router by enabling IP forwarding in registry.

You need to have two network cards installed on your router machine (windows xp machine), both connected to network switches of two different networks.

Two network cards on the router are having following configuration

Router (Windows XP Professional)

Network Card X (connected to switch of network X):
IP Address: 172.16. 1 .1
Netmask: 255.255.255.0
Gateway: Blank

Network Card Y (connected to switch of network Y):
IP Address: 10.0.40.1
Netmask: 255.255.255.0
Gateway: Blank

All computers in network X should have following configuration.

IP Address : 172.16. 1.2 to 172.16. 1.254
Netmask: 255.255.255.0
Gateway: 172.16. 1 .1

All computers in network Y should have following configuration.

IP Address: 10.0.40.2 to 10.0.40.254
Netmask: 255.255.255.0
Gateway: 10.0.40.1

Now to make these two networks communicate Configure IP forwarding

Go to Start and click Run

Type in regedit to run registry editor.

Go to the following registry key at the left hand side tree

HKEY_LOCAL_MACHINE-SYSTEM-CurrentControlSet-Services-Tcpip-Parameters

Right click IPEnableRouter and click Modify.

In IPEnableRouter window Type 1 as Value data and click OK.

Close the regisrty editor and reboot the computer to make new settings effective.

Your XP router is ready and and your different series networks can communicate to each other without any Router