OPNsense Forum

English Forums => Virtual private networks => Topic started by: ita.tc on November 27, 2025, 01:46:01 PM

Title: OPNsense as OpenVPN Server behind another firewall
Post by: ita.tc on November 27, 2025, 01:46:01 PM
Hi all,

I would like to setup an OPNsense behind another firewall to provide OpenVPN Road warrior connections into a network. I thought "how hard could it be?", set up a new OPNsense, disabled the WAN interface, configured LAN with a static IPv4 and added the existing firewall as gateway. Added port forwarding for management interfaces (temporarily for deployment) and 1194 UDP in that firewall and configured an OpenVPN instance on the OPNsense. Remote Access worked instantly, but I can't get OpenVPN to work. It seems like am missing an important step here. I read some posts and found this one (https://forum.opnsense.org/index.php?topic=25476.0), which seemed promising. Sadly I must have messed up since disabling the Anti-lockout rule locked me out of the admin interface. I did create my own rules allowing access beforehand but I might have forgotten to hit "apply" like a total noob.
So now I'm looking to understand this issue before making another attempt. I had something similar running on a Synology NAS with their VPN Server and really didn't expect to run into so many issues. We have quite a few OPNsenses deployed successfully, but not with only one interface. If I could I would replace the existing firewall but that is currently not possible.
Any help in this matter will be greatly appreciated.
Title: Re: OPNsense as OpenVPN Server behind another firewall
Post by: viragomann on November 27, 2025, 02:18:53 PM
Quote from: ita.tc on Today at 01:46:01 PMbut I can't get OpenVPN to work.
What does this mean?
Are you able to connect to the VPN?
If yes, ensure, that there is an allow-any rule on OpenVPN and try to access the web GUI.

Or do you have issues accessing other local devices?