Remote phone registers and can call external, but not internal

Hi Everyone, I have a FreePBX behind a Fortigate router with ports 5060 and 10000-20000 forwarded. I also have the TFTP ports forwarded and the policy is locked down by external IP so that only remote workers’ homes are allowed in. Remote phones (Yealink SIP-T23G) can register, download configuration files from FreePBX, and they can call outside numbers like 262-XXX-XXXX, but they CANNOT dial internal extensions. Phones that are inside the network can reach the remote phones by dialing their extension or their DID, but again remote phones cannot dial internally to other phones inside the network. Any ideas?

Please trap the call (Linux CLI: asterisk -vvvvvvvvvvr) and post the log here. You can also get it from /var/log/asterisk/full, but there’s lines that can’t be associated well via grep so I don’t recommend it.

It looks like this issue was resolved by using a different ISP from the remote location. AT&T Uverse was doing some SIP filtering and I cannot disable the SIP helpers/alg on the home router. Oh well!

They blocked SMTP just for lulz over here; I had to call them and have them unblock it.