Using a VPN client with Windows XP SP2

 

Posted 11-10-04

 

After installing Service Pack 2 for Windows XP you will probably find that your VPN client no longer works!!

 

A fix has now been identified that will allow the VPN client to work; you will need to add the following registry key….

 

HKLM\System\CurrentControlSet\Services\IPSec\AssumeUDPEncapsulationContextOnSendRule

 = REG_DWORD

The value data should be set to equal 2.

You can reset the behaviour to Default SP2 by changing the Value to “0”.

A value of “1” will only enable a Client with a public (i.e.non-NAT’d) address to connect to a NAT’d server.

The value of “2” enables both public and NAT’d clients to connect to a NAT’d server.

The value of “2” is equal to the pre-SP2 behaviour.

You can download the Registry key HERE  - (Right click and select ‘Save Target As… rename to XP_SP2_VPNfix.reg’)

NOTE… XP sp2 seems to rename .REG files to .MP3!! …

When you click the ‘Save’ button, rename the file to ‘XP_SP2_VPNfix.reg’

You can then double click the file to install the required keys.