H.323 Calls Port Reference
Purpose Src. IP Src. ports Protocol Dest. IP Dst. Ports
Initial
RASconnection
External address of
firewall protecting off-
premises endpoint
>=1024 UDP Expressway-
E (public)
1719
Initial
RASconnection
Expressway-C 1719 UDP Expressway-
E (private)
6001 (for first traversal zone,
6002 for second etc.)
Q.931 / H.225
signaling
Any (endpoint in the
Internet)
1720 TCP Expressway-
E (public)
1720
Q.931 / H.225
signaling
Expressway-E (public) 15000-
19999
TCP Any
(endpoint in
the Internet)
1720 (endpoint signaling port,
specified during registration.
Could be another port
>=1024)
Q.931 / H.225
signaling
Expressway-C 15000-
19999
TCP Expressway-
E (private)
2776 (Assent calls)
Q.931 / H.225
signaling
Expressway-C 15000-
19999
TCP Expressway-
E (private)
1720 (H.460.18 calls)
H.245 Expressway-C 15000-
19999
TCP Expressway-
E (private)
2776 (Assent calls)
H.245 Expressway-C 15000-
19999
TCP Expressway-
E (private)
2777 (H.460.18 calls)
H.245 Any (endpoint in the
Internet)
>=1024 TCP Expressway-
E (public)
Expressway-E (public)
H.245 Expressway-E (public) 15000-
19999
TCP Any
(endpoint in
the Internet)
>=1024 (endpoint H.245
signaling port)
H.245 External address of
firewall protecting off-
premises Assent endpoint
>=1024 TCP Expressway-
E (public)
2776
H.245 External address of
firewall protecting off-
premises H.460.18/19
endpoint
>=1024 TCP Expressway-
E (public)
2777
RTP
(multiplexed
traversal media)
Expressway-C 36000-
59998
(even
ports)
UDP Expressway-
E (private)
2776 (Small/Medium)
or 36000-36010 (even ports)
(Large)
RTCP
(multiplexed
traversal media)
Expressway-C
36001-
59999
(odd ports)
UDP Expressway-
E (private)
2777 (Small/Medium)
or 36001-36011 (odd ports)
(Large)
Table 10 H.323 Ports Reference
20
Cisco Expressway IP Port Usage Configuration Guide