When the system is installed behind a firewall/router that is using NAT, certain ports has to be opened to use the following services.

Port numberFor protocolIs used for
80TCPHTTP
443TCPHTTPS
5060UDPSIP
10000-20000UDPRTP
4569UDPIAX
123UDP or if necessary TCPNTP, if this is to be used to control the system time
5222/5223TCPXMPP, for instant messaging and the Gigaset T300 PRO / Gigaset T500 PRO Win Client. Port 5223 is used for secure connections with SSL
3090TCPJMS, for setting up and using an interconnection