I guess this thread comes closest to what we’re witnessing FreePBX can’t see extensions real IP
Unfortunately, no resolution, but the explanation hovers around doubting the router, which is a strong suspect in my opinion too. I did look at all possible configuration in this Aztech DSL8800GR router but to no avail. Frankly I don’t know what I should be looking for - I generally looked for NAT or SIP related settings, and there are none. Just the port forwarding rules that we’ve added.
But the fact that “sip show peer” is showing correct source IP in Reg. Contact field but replacing it with PBX IP in the Addr->IP field and using that to display as Host in Chan_sip Peers report is puzzling and causing me to also doubt some config in Asterisk playing up.