How to disable the IP Spoof Detection feature in ISA Server 2004,2006

Click this link http://support.microsoft.com/kb/838114

To disable the IP Spoof Detection feature in the Windows registry, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/FwEng/Parameters
   If the Parameters subkey is not displayed, follow these steps to create this subkey:
   1. Click the FwEng subkey.
   2. On the Edit menu, point to New, and then click Key.
   3. To name the key, type Parameters, and then press ENTER.
3. Right-click Parameters, point to New, and then click DWORD Value.
4. To name the value, type DisableSpoofDetection, and then press ENTER.
5. Right-click DisableSpoofDetection, and then click Modify.
6. In the Value data box, type 1, and then click OK.
   
   Warning This setting disables IP Spoof Detection. To enable IP Spoof Detection, set the DisableSpoofDetection value to 0. This is the default value.
7. Exit Registry Editor, and then restart the ISA Server 2004 services or the ISA Server 2006 services.