WAN not working after connected to wrong port

[sensorback]

Hi Forum,
I'm running 18.1.6/18.1.7 on an APU2C4 with three Intel NICs. It worked for about two weeks. Then I did some tweaking, and also moved the WAN port to the other side of the box. Now it happens, that you configure, before you physically move the cable to the other port, or the other way around - however: the WAN cable (coming from an LTE modem) is attached to an unconfigired or a LAN port. When I move the WAN cable to the correct port again, i don't get online. Pings to 8.8.8.8, browsing on a client, checking for updates in the OPNSense GUI, nothing works. The steps to repair it are different. Stopping the whole infrastructure sometimes works, saving the WAN gateway, and just messing around a bit, reinstalling OPNSense, sometimes one of this steps works, sometimes not. Today it just worked after waiting 16 hours doing NOTHING.

At least after doing the OPNSense setup with all defaults, so that I can be sure nothing is messed up, one would think it's done - but no, not always.

There is only the LTE modem (Netgear LB1110) and my PC attached (i leave out all other infrastructure until this is solved). Anybody else with this issue?

[seamus]

Your problem reminds me of an issue I had a few years ago. It drove me insane (never quite recovered btw)... I had put my Comcast cable modem in "bridge mode" to avoid double-NAT'ing, and one or two other reasons I don't recall now. Connected my firewall to it, configured, etc... It worked for weeks like that.

I had another appliance I was using as a cold spare, and it was identically configured to the first box. But when I swapped, nothing worked - nothing!

Turned out that the modem would only talk to that first MAC address - no other MAC address would do. Fortunately, this was easy to deal with in pfsense at the time, and is still in OPNsense.

Maybe it's that? Is your modem in bridge mode?

[dcol]

I had an issue like that and had to delete the gateway and reinstall. Ask the ISP to reset their ARP tables and check the gateway settings.