My provider only gives me a url, not an IP. I will ask them if an IP is available, and I am running Fail2Ban and I get emails from it telling me its blocking IP’s.
Tangentially they are the ONLY emails that work, the VM emails generated by Freepbx are blocked by o365 and due to the SIP issue I haven’t been able to relax and divert my attention there yet. But its so odd that Fail2Ban CAN be received where freepbx cant. the sender address I imagine. I’ll get to that later.
But you say that even with these log entries, the sip failure I see so often is likely to be something else? Would your first guess be the normal provider failures, or something VOIP or FreePBX specific?