OPNSense plugin error when starting gateway "Couldn't create network interface wgX"

[maxime-morel]

Hello,

I'm using the plugin defguard-gateway 1.2.1 on OPNsense 25.1.1-amd64 (and facing also the issue in previous version 24.7) .

When OPNSense restart or when the core disconnect and reconnect, there is an issue recrating the interface wg1
Warning defguard-gateway Couldn't create network interface wg1: BSD error: Write error EEXIST: File exists. Proceeding anyway.

This is braking the gateway and a manual action has to be performed to:

• Change my interface assignment to remove the association with wg1
• Manually destroying my interface sudo ifconfig wg1 destroy
• Restarting the plugin (button Start/Restart)

More details on my configuration:

• Defguard gateway plugin default setup with minimal options (no pre/ post up/down)
• Interface [Defguard_wireguard] created (opt3) with assignment to Device wg1
• Firewall rules configured follwoing https://docs.opnsense.org/manual/how-tos/wireguard-client.html

I believe that the issue might be due to the fact that I'm assigning wg1 to an Interface. I've done that to be able to assign Firewall rules and monitor my interface. I'm using this gateway as a WAN output so my remote peers can tunnel their internet connexion to my firewall.

Any idea how this issue could be fixed and if this is a know issue?

Thanks!