The ENUM trunk does not need a SIP provider to log on. An ENUM trunk directly accepts the SIP messages from the opposite terminal. In order to support this scenario, the NAT router must have port forwarding configured so that the SIP messages, which are received on the public IP address of the NAT router on well-known port 5060 are also forwarded to the LinkManager on port 65002 in the internal network. To do this, create a rule on the NAT router that forwards all messages received on the public IP address an the port 5060 from the NAT router to the internal network to the IP address of the LinkManager and the port 65002.

This will ensure that the SIP messages are also received by the LinkManager.

Example:

Placing the LinkManager in a DMZ (Demilitarized Zone) is not recommended because the clients must contact the LinkManager directly for voice transmission and a real DMZ cannot usually be accessed by LAN clients.