I am trying to get a remote extension to register via a site-site VPN connection. The SIP phone/client comes back with a 408 error. After much troubleshooting, I decided to install a fresh new copy of Elastix with FreePBX all updated to current releases. I configured this to have the same IP address as the “broken” PBX server (having shut down the old one). I added a new extension in this system and the remote phone registers fine. I did this to make sure I was not having other issues related to the firewall/router/VPN. So I assume this removes that from play.
I have looked though many of the /etc/asterisk config files to see what the differences are of the working and not working servers. I cannot find anything that stands out. I tried backing up the config files from the old server and restoring them on the new server to see if it might be a linux config issue. However the restored config from the old server onto the new server failed also.