Has anyone successfully setup Bandwidth.com SIP Trunks?
They provide 2 main IP address, then multiple media IP address for each.
Bandwidth SIP (Session Initiation Protocol) signaling protocol is designed for RFC3261. If any other method is used, calls will fail to set up.
Allowed ports for media and audio
If your PBX is protected by a firewall, the manufacturer compliance will need to be verified that the firewall has the ability to act as either a SIP ALG or a Back-to-Back User Agent (B2BUA). The following ports are required to allow for full 2-way audio:
UDP port 5060 – must be opened to support SIP signaling and is the default port for Bandwidth.
UDP ports 1024-64,000 – must be opened either statically or dynamically (ALG) to allow for audio path.
Bandwidth will use multiple IP addresses to allow media from its gateways.