L2TP/IPSEC SERVER ISSUE

[Faster_VPN]

Hey Guys,

I am trying to make a new server, I can connect with the SoftEther Client perfectly however when I try and connect to the L2TP vpn on my laptop to my server it won't work, giving the following error message - ERROR 789: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

Any help as to why my server isn't working would be appreciated.

[inten]

FAQ! Why don't you use Google? This is so simple and time-saving.

5) Error Code: 789
Error Description:
789: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

Possible Causes: This is a generic error which is thrown when the IPSec negotiation fails for L2TP/IPSec connections.

Possible causes for this issue could be:
a> L2TP based VPN client (or VPN server) is behind NAT.
b> Wrong certificate or pre-shared key is set on the VPN server or client
c> Machine certificate or trusted root machine certificate is not present on the VPN server.
d> Machine Certificate on VPN Server does not have 'Server Authentication' as the EKU

Possible Solution: Make sure correct certificate is used both on client and server side – for further details refer to this blog. In case Pre Shared Key (PSK) is used, make sure the same PSK is configured on the client and the VPN server machine.

http://blogs.technet.com/b/rrasblog/arc ... rrors.aspx

[Faster_VPN]

The problem is that the server is behind NAT - I've looked on google about getting around it, and can't find a solution as the server is in a Datacenter. If you have a solution I'll let you remote desktop onto the server and see if you can sort out the issue. I haven't had any luck so far.

[thisjun]

Did you open ports 500/UDP and 4500/UDP on NAT?