How to Enable TCP/IP Forwarding in Windows XP

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This article was previously published under Q315236

For a Microsoft Windows 2000 version of this article, see 230082 (http://support.microsoft.com/kb/230082/EN-US/ ) .

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SUMMARY

This article describes how to enable Transmission Control Protocol/Internet Protocol (TCP/IP) forwarding on a Windows XP-based computer. By default, TCP/IP forwarding is not enabled in Windows XP.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows

To enable TCP/IP forwarding, follow these steps:

Start Registry Editor (Regedit.exe).
In Registry Editor, locate the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
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.
Quit Registry Editor.