VPN Connection Error

[gman2k2]

We have clients (all using W2K machines) connecting to our network (W2K server) through a VPN. All the clients are able to establish their connection using PPTP. If they attempt to force an L2TP connection, they are unsuccessful. The receive error 791 (security policy not found). All these clients have the correct certifcates (stored on local machine store and user store). We have been trying for some time to get this resolved, with no luck. Has anyone else run into this?
Thanks.

 

[Guest_imported]

Just curious why you are trying to use L2TP if PPTP works. From what I know, PPTP allows a client to connect to a server by accessing the IP of the server (or whatever public IP address is available for the server). It is more or less a direct connection. For example, if you dial the RAS local to the PPTP server you can log in.

L2TP on the other hand has an extra component involved. With L2TP you dial into a local RAS (called a LAC). The local RAS authenticates you then connects to another server or RAS (called the LNS) located at the endpoint whereby another authentication request may or may not occur. This second connection typically is over the Internet. In affect the L2TP tunnel actually is set up between RAS's, not directly from client to server. The advantage is you can dial into a RAS local to your location instead of potentially dialing into a remote RAS which might be long distance.

This is a simplified explanation. Both PPTP and L2TP are similar in terms of level of encryption,etc. Check out

http://www.protocols.com

and do a search for L2TP for more detailed info.