VPN solutions for NT 4 Domain

I am trying to set up a VPN on an NT 4 domain. I have tried using WIN2K for the VPN server. This is in a NT 4 domain with an NT 4 PDC. I cannot get the VPN server to validate users using the NT4 PDC. Is there any special way I should be setting thisup or should I be using PPTP on NT 4 RAS instead?