Problem with L2TP Connection

[Andrey029]

Hello,
I'm setup softehter vpn server, on the PC with private IP address, and i can connect to server using MS-SSTP and Softether VPN Client, but i can't connect to server using L2TP, why? (ports (UDP 500 and 4500) are opened.)

[moatazelmasry]

Did you enable l2tp?
what is the client?
What are your configurations?
what does the logs say?
Please provide more info

[Andrey029]

moatazelmasry wrote:
> Did you enable l2tp?
> what is the client?
> What are your configurations?
> what does the logs say?
> Please provide more info

Ofcourse, I enable l2tp.
The client is iOs and Windows 7 l2tp.
Configurations are Windows 7 x32, SoftEther VPN Server Version 4.20 Build 9608, SecureNAT is disabled.
In attach more info.

Is it can be that l2tp doesn't work through vpnazure?

[moatazelmasry]

Hmm. In the server log, there's nothing related to l2tp, as if the first connection does not even make it to the server

L2TP protocol requires port 1701. Please open it as well
I'm not sure whether L2TP need ports 500 and 4500 (probably not), but it doesn't harm to test these as well

From the client machine(a linux), could you please try the following command
nc -vnzu ${VPN_SERVER_IP} ${PORT}

With the ports: 500,4500, 1701

Make sure to use IPs and not dns names for this command. You should get
Connection to $SERVER_IP $PORT port [udp/*] succeeded!
For the three port

[Andrey029]

I think it is because of vpnazure.net.
I made some tests on PC that has a static ip address and when I connect to the server through ip address or ddns.softether.net l2tp connection is working, but if I use ddns.vpnazure.net l2tp connection isn't working.