L2TP vpn on softether vpn server (no public IP)

[yanggis]

Dear all,
Softether vpn is really an amazing product. I want to try setup my Softether vpn server for personal use only. However, my laptop doesnt have a public ip in the work place. After running the server, I can smoothly connect the server using Softether client on Windows 7.
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.
The issue may be caused by the problem that the windows L2TP client cannot comunicate with the server because the server has no a public ip addess.
Anybody knows how fix this problem?

[dajhorn]

You must put a network monitor on the SoftEther server to diagnose this kind of problem. At a minimum, you should provide the SoftEther logs for the connection failure.

However, it is likely that the corporate firewall is blocking L2TP traffic, which is easy to detect. Try something like SSTP instead.

[thisjun]

Is your VPN server under a NAT?