Working behind a firewall or router

If you have multiple users behind a firewall or router then you will probably need to enable NAT Traversal on the SIP server (see SIP - Advanced tab).

The following diagram shows a call using NAT traversal and proxy ports.

Figure. Example of a call using NAT traversal and proxy ports.

The basic functionality is the same except that all communication outside of the domain is done via a proxy port.

One proxy port is opened for each User communicating outside the domain.