https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X12- 5/Cisco-Expressway-IP-Port-Usage-for-The internal firewall must allow the following outbound connections from the Expressway-C to the Expressway-E: SIP: TCP 7001 Traversal media: UDP 2776 to 2777 (or 36000 to 36011 for large VM/appliance) XMPP: TCP 7400 HTTPS (tunneled over SSH between C and E): TCP 2222