2K3 sp2 kills VPN access

 First i installed ADAM (Active Directory Application Mode) from the Win2k3R2 CD. The version of ADAM at the Win2k3R2 cd is ADAM Service Pack 1. Older versions of Win2k3 don't have ADAM Service Pack 1, so when you run an older version you have to install ADAM from your cd, and then upgrade ADAM to ADAM Service Pack 1.

After that i edited my registry, the EnableRSS key has to be at 0 in stead of 1. If you cannot find the EnableRSS key, you have to create it in the folder Parameters and set it to 0.
The key can be found here (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableRSS)

Make sure your PPTP Filter is set on. This filter option you can find in your ISA Management under >Protocols >VPN >PPTP (Server)

Double click the PPTP protocol and click the Parameters tab. On the bottom you will find the used filters, make sure the PPTP Filter is switched on. Redo the last steps on the PPTP Server protocol and your PPTP VPN connections should work without problems under Service Pack 2.