Have an SG-1000 between a Windstream DSL modem (in bridge mode) and a Grandstream UCM6208 PBX. PPPoE authentication handled by the pfSense.
Recently, the firewall will alert that it is "reset after being wedged." The Grandstream PBX then unregisters the SIP trunk, but still sends me an SMTP email alert that the trunk is not registered (so obviously the internet still works). I'm able to remotely access the pfSense and reboot, which restores the SIP trunk. I'm wondering if it's a firmware issue, or if there is a particular firewall setting that would allow this outbound registration (5060, I believe) traffic to be reset (if the "wedge" is what prevents the traffic).
Happy to post specific logs, as needed.
You would probably want to examine the firewall logs for the time it is not reconnecting and see if anything is blocked.
You might also want to look at the state table and see what states are established on behalf of the PBX and see if that gives you any indication why it isn't working.