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OpenVPN Unstable/Unsable - ISP blocking it?

Posted: Tue Aug 06, 2019 9:00 am
by BY_Zaca
Hi.

I have a openvpn server running on a dedicated server and it works amazingly fine on a Computer "A" that uses the internet "A".

However, a Computer "B" that uses the internet "B" is unstable on a point that you cant even surf on the internet.

Image

192.168.1.1 = Router gateway
10.10.10.1 = openvpn gateway

I have tried connecting over TCP and UDP, tried changing the default ports to random ports, tried windows and linux, tried different computers from the "Internet B" network, tried connecting the modem directly on the computer and setting up the PPPOE (the ISP uses this protocol to provide internet) to prove that the router was not blocking openvpn, tried lowering the PPPOE and Openvpn MTU, tried different VPN server on a completely different server with a completely different route but still exactly same problem.

Direct TCP and UDP connection from this Computer B to the server where is running the openvpn server is fine, no packet loss and i can get full speed. Things gets bad when i connected on the vpn. The funny thing is that PPTP and L2TP also works fine on this server where openvpn is running.

Any one ever had something similar?
Thanks!

Re: OpenVPN Unstable/Unsable - ISP blocking it?

Posted: Fri Sep 06, 2019 9:21 pm
by BY_Zaca
The funny thing is...

If i use a software from VPN providers using openvpn protocol, it is stable and work very well. If i download the openvpn profile file that connect on the same server/encryption and import to use with the native openvpn client, it work very unstable on a point that is umsable like on the photo above.

Any idea on what the issue could be?

Re: OpenVPN Unstable/Unsable - ISP blocking it?

Posted: Fri Sep 06, 2019 10:57 pm
by TinCanTech
Your internet B looks to be awful ... but what do we know about internet B ?

Re: OpenVPN Unstable/Unsable - ISP blocking it?

Posted: Sat Sep 07, 2019 6:22 am
by BY_Zaca
The internet B is a FTTH 300/150MB (Telefonica, that spanish company) and work very well when not using openvpn. PPTP/L2TP and softwares from vpn providers (using openvpn "protocol") also work very well and i can get full speed. But if i use native openvpn software importing the client file from those vpn providers, it is impossible to use.

Just does not make any sense using same protocol and having completely different performance.
Very weird, any ideas?

Re: OpenVPN Unstable/Unsable - ISP blocking it?

Posted: Sat Sep 07, 2019 12:48 pm
by TinCanTech
If you are connecting to your own server See:
viewtopic.php?f=30&t=22603

If you are connecting to a VPN service provider then please contact their support.