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3CX Phone System for Windows System for Windows
Page 17
3CX Phone System behind a NAT / firewall
The best place for 3CX Phone System is on a machine
behind the firewall. This
configuration is easier and more secure. If you will just use PSTN lines, you don’t even
need to make any changes to your firewall configuration.
If you intend to use a VOIP Provider, then you will need to open the following ports to
allow 3CX Phone System to communicate with the VOIP Provider:
Port 5060 (UDP) for SIP communications (send & receive)
Port 3478 (UDP) for communication with the STUN server (send & receive)
Port 9000-9003 (or higher) (UDP) (send & receive) for RTP communications, which
contain the actual call. Each call requires 2 RTP ports, one to control to call and one
for the call data. Therefore, you must open twice as many ports as you wish to
support simultaneous calls via the VOIP provider. For example, if you want to allow
4 people to make calls via the VOIP provider simultaneously, you must open port
9000 to 9007.
Note that the above port ranges are the default ports in 3CX Phone System. You can
adjust these ports from the Management Console, in the General > General Settings
page. In this page, you can configure the ports to be used for internal calls, and the ports
to be used for external calls being made via a VoIP provider.
Firewall installed on the 3CX Phone System machine
If your phone system is running on the internal network behind a firewall, it is not
necessary to enable the firewall on the machine running 3CX Phone System. However if
you wish to do this, then you will have to open the following ports:
Port 5481 (TCP) for the 3CX Phone System management console
Port 5060 (UDP) for the SIP server
Port 3478 (UDP) for communication with the STUN server
Port 7000 to 7500 (UDP) for internal calls (or higher if you have more then 250
extensions).
Port 9000-9003 (UDP) for external calls via a VOIP provider. Each call requires 2
RTP ports, one to control the call and one for the call data. Therefore, you must
open twice as many ports as you wish to support simultaneous calls via the VOIP
provider. For example, if you want to allow 4 people to make calls via the VOIP
provider simultaneously, you must open port 9000 to 9007.
Note that the above port ranges are the
default ports in 3CX Phone System. You can
adjust these ports from the Management console.