We have Sangoma S305 phones setup with a VPN using the FreePBX built-in VPN server. We have been able to establish the VPN connection by going out our first WAN (Comcast Business Modem) and back in through the second WAN (Windstream Modem). However the first user we sent a phone to has a Residential Comcast Modem and we are unable to establish a connection. We can see that the VPN is getting to the set destination (the Windstream public IP forwarded to the PBX machine) but gives this message when tailing /var/log/messages:
Mar 26 14:34:59 vox openvpn: 126.96.36.199:46339 TLS: Initial packet from [AF_INET]188.8.131.52:46339, sid=783cf068 ea63757c
Mar 26 14:35:59 vox openvpn: 184.108.40.206:46339 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Mar 26 14:35:59 vox openvpn: 220.127.116.11:46339 TLS Error: TLS handshake failed
Mar 26 14:35:59 vox openvpn: 18.104.22.168:46339 SIGUSR1[soft,tls-error] received, client-instance restarting
It is almost certainly something in the Comcast residential modem as far as we can tell given the relative ease of success with our business modem, has anyone been able to make this work with this ISP? We have tried placing the phone in the DMZ as well as port forwarding 1194 to the phone itself and still no luck, thanks for any advice!