Several of our office users were excited about AT&T’s WiFi Calling rollout this past week. We work in a moderately populated area, but are plagued by unfortunate office positioning with a nice and sturdy metal roof. So far, with limited testing, the results are fabulous and users at the back of the office are now receiving crystal clear voice calls.
One area we expected some pain was in the firewall setup. We block both inbound and outbound traffic unless specifically allowed and WiFi Calling uses some non-standard ports.
I searched the web and could not find any reasonable documentation for ports to open so a little watching of the firewall and we were able to find the culprit ports. Posted here for your reference: if you need to enable AT&T WiFi Calling through your firewall, in addition to standard SSL ports that should be open, be sure you allow traffic from these ports as well:
Destination IP: 220.127.116.11* Protocol: UDP Destination Port:500
*your ip address milage may vary depending on your location