The corporate LAN hosting the IP Office system requires a public IP address that is routed to the LAN interface of the IP Office system configured for remote H.323 extension support.
STUN from the IP Office system to the Internet is used to determine the type of NAT being applied to traffic between the system and the Internet. Any routers and other firewall devices between the H.323 phone location and the IP Office system must allow the following traffic.
Protocol
Port
Description
ICMP
-
Incoming ICMP to the IP Office system's public IP address must be allowed.
UDP
1719
UDP port 1719 traffic to the IP Office system must be allowed. This is used for H225 RAS processes such as gatekeeper discovery, registration, keepalive, etc. If this port is not open the phone will not be able to register with the IP Office system.
TCP
1720
TCP port 1720 traffic must be allowed. This is used for H.225 (call signalling). The address used can be adjusted using the Remote Call Signaling Port setting.
RTP
Various
The ports in the range specified by the system's RTP Port Number Range (NAT) settings must be allowed.
RTCP
UDP
5005
If the system setting Enable RTCP Monitoring on Port 5005 has been enabled, traffic on this port must be allowed to include remote H.323 extensions in the monitoring.
User Network Configuration
It is assumed that the domestic router allows all outbound traffic from the home network to pass through and allows all symmetric traffic. That is, if the phone sends RTP/RTCP to a public IP address and port, the router allows it to receive RTP/RTCP from that same IP address and port.
