VPN connections stopped working suddenly

Post your questions about SoftEther VPN software here. Please answer questions if you can afford.
Post Reply
rcooke
Posts: 4
Joined: Wed Apr 12, 2017 3:28 pm
Contact:

VPN connections stopped working suddenly

Post by rcooke » Sat Dec 02, 2017 5:38 pm

I setup SoftEther 3 a while ago and it worked great! My setup has a Modem, Router, 1G switch, and SoftEther running on a small Win10 PRO box.

I noticed it was not working (unable to connect) a few weeks ago. No idea why it stopped working. I had upgraded my router and modem, but put back the same port-forwards I had before (as listed in the SoftEther manual).

I noticed there was a new version of SoftEther available so I updated to it (4). I enabled both cloud connect methods, both show "connected" in the status panel.

I tried connecting from my iPhone using the IP address, both clouds, and my own DDNS name. Every attempt gets "server did not respond" error.

For a test, I used a web browser to try and connect with https. I get an error, which I expected since its trying to use HTTP instead of VPN, This is the error message:
Forbidden
You don't have permission to access / on this server.
HTTP Server at 10.0.0.15 Port 443

To me the important thing is the server address is 10.0.0.15, which is the machine I run SoftEther on (a Win10 PRO box). So my port forwards must be working.

But what can prevent it from reaching SoftEther?

I setup the firewall exceptions when I first installed it, and it was working great for many months.

I am hoping this is something somebody has seen before!

UPDATE:
I was able to connect to the VPN server from inside my home network with my iPhone! Which suggests SoftEther is listening ok, and there is something wrong with my port forwards. Now I am more confused!

UPDATE2:
My new router (Asus RT-AC66U_B1 firmware 3.0.0.4.382_18881) has OpenVPN server built in. So I enabled that for a test. It uses UDP packets on port 1194. The modem generates a key-setting file. I installed the OpenVPN app for iOS V1.1.1 and e-mailed myself the key file. I opened the keyfile in Open VPN, off of my WiFi, and it connects to my modem and seems to work. Great to have a backup until I figure this out.

But then while poking around in the settings for SoftEther I re-discovered it emulates Open VPN too! So I generated its key-setup file, changed it to TCP. I was expecting the app to let me set the port to 443, 992, or 5555. I did not expect 1194 to work since the router is using it.

After e-mailing myself the file, opening it in OpenVPN, entering my SoftEther credentials, I can connect. Looking in the Open VPN app log I see it resolved my IP using the SoftEther DDNS cloud, the first connection failed. The second, using port 1194 and TCPV4 worked! I do not see anyplace in the app to specify the port to use.

My confusion deepens. Why does this work but not L2TP? Why does it work on the same port # as the router?
Thanks in advance!

Rich.

rcooke
Posts: 4
Joined: Wed Apr 12, 2017 3:28 pm
Contact:

Re: VPN connections stopped working suddenly

Post by rcooke » Thu Dec 07, 2017 1:02 am

I think I fixed it!

The SoftEther manual talks about ports 443, 992, 1194 and 5555 all over the place. I added those to my new router as port forwards to the VPN server.

BUT

Only after digging like crazy did I realize that IOS Apple products DON'T USE these ports!! Something I must have figured out before, but forgot.

For L2TP to work you have to also port forward UDP packets on ports 500, 1701, and 4500.

I'm documenting this here and elsewhere in the hopes that next time I will discover this note before I go crazy!
Thanks in advance!

Rich.

Post Reply