audio.sip.UserAgentPort

Port of the SIP user agent listener.

Valid values range from 4096 to 64000. Each instance of a SIP user agent on a machine must be unique. If more than one instance share the same port, only the first to be instantiated receives messages; the other instances stay idle until the previous instance shuts down. The default depends on the Telephony Session service instance: 5060 (first instance), 5070, 5080, and 5090.

For more, see SIP audio provider settings.