Using Network ports

Last Updated : Oct 07, 2026 |
Prolog information
The main server(s), Survivable Remote Servers and each Survivable Core Server use specific TCP or UDP ports across a customer’s network for registration and translation distribution. The following Network port usage provides information to determine which TCP or UDP ports must be open in your network for a Survivable Remote or Survivable Core Server. Check the firewalls on your network to open the required TCP or UDP ports.
Network port usage
Port
Used by
Description
20
ftp data
21
ftp
22
ssh/sftp
68
DHCP
514
Used in Communication Manager 1.3 to download translations.
1719 (UDP port)
The survivable servers to register to the main servers
UDP outgoing and incoming
1024 and above
Processor Ethernet
TCP outgoing
1039
Encrypted H.248
TCP incoming
1720
H.323 host cell
TCP incoming and outgoing
2945
H.248 message
TCP incoming and outgoing
5000 to 9999
Processor Ethernet
TCP incoming
21873 (TCP port)
The main server(s) running Communication Manager 2.0 to download translations to the Survivable Remote Server(s)
Prior to an upgrade to Communication Manager 3.0 or later, servers running Communication Manager 2.x used port 21873 to download translations to the Survivable Remote Server(s). Once the upgrade to 3.0 is complete and all servers are running versions of Communication Manager 3.0 or later, the main server(s) uses port 21874 to download translations and port 21873 is no longer needed.
21874 (TCP port)
The main servers to download translations to the survivable servers.
A main server(s) uses port 21874 to download translations to the Survivable Core Server (s) and the Survivable Remote Server(s) on Communication Manager 3.0 and later loads.
To configure the ports on your server, click Firewall under the Security heading in the Server Administration Interface.