[Noob] Problems with DEC3842 (i hope i didnt brick it)

[hseitz]

Hello,
i am a 45 years old Software-Developer with some (very) basic networking knowledge. We are a small company that is using a OpnSense DEC3842 behind a Fritzbox which we want to use as modem only. The fritzbox has a static public IP provided by the ISP.

I unpacked the device and did some basic configuration, e.g:
- WAN (Port1) connected to the fritzbox, static ip address 192.168.1.21
- LAN (Port0) configured to assign IP addresses to clients using DHCP on 192.168.0.0/24

So far everything looked ok.
Then i wanted to expose port 8080 on a VM on the LAN to the public internet, so that users from the internet can use http://<public-ip-of-fritzbox>:8080.
I was able to access <ip-of-vm>:8080 from the 192.168.0.* subnet, but not from the 192.168.1.* subnet.
This is probably when the desaster started: i assumed that i had to add a route from WAN to LAN and created a route like this (if i remember correctly): 192.168.1.* -> 192.168.0.1 (ip of opnsense on LAN).

That must have caused a lockout: i am not able any more to connect to the web interface of the opnsense. Neither using 192.168.1.21 (my PC connected to the fritzbox), nor 192.168.0.1 (my PC connected to OPNSense LAN).

I was desperate, so i tried to
a) reset using the reset button on the front
b) power off / on
c) factory reset using long press the reset button on the front (i dont even know if this is possible)

What shall i do?
Probably connect using console via usb cable, correct? But what next?

Please help!

Regards,
Holger

[Patrick M. Hausen]

Probably connect using console via usb cable, correct? But what next?

Exactly this. Start a terminal program like minicom on the connected system, settings 115200, 8N1, hardware handshake - you will be greeted with a nice menu, offering among other things to reconfigure interfaces. Or invoke a shell and manually delete the route.

[dseven]

One of the items in the menu presented on the serial console should be "Restore a backup" - pick one from before you added the route.

[hseitz]

Great, thanks to both of you!