Enable Routing on Windows XP

To enable TCP/IP forwarding, follow these steps:

1. Start Registry Editor (Regedit.exe).
2. In Registry Editor, locate the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. Set the following registry value:
Value Name: IPEnableRouter
Value type: REG_DWORD
Value Data: 1
A value of 1 enables TCP/IP forwarding for all network connections that are installed and used by this computer.
4. Quit Registry Editor.
5. Restart the machine