Microsoft L2TP connection from behind PIX

[cboykin]

Hi,

I'm trying to get a Microsoft native L2TP VPN client to go from behind my PIX to a VPN site on the Internet. It doesn't work. My PIX is running PAT for the outbound connections. My client gets to the "Verifying username and password" stage and hangs.

Suggestions?

[scoclayton]

It's been a while since I screwed around with L2TP but I recall that one of the biggest limitations to L2TP is that the original packets cannot be NAT'ed at all. That is, not PAT'ed nor 1:1 NAT'ed. The packets have to arrive at the termination device unchanged. You may want to check into this and make sure my info is not outdated.

Hope this helps.

Scott

[mostiguy]

there is a ms update that provides some nat-t support to l2tp, but i have no idea how effective it is. i believe it is a separate download for win2k and xp, and is included in xp sp2