14.5.2.1. Configuration 
The feature is configured in two or three steps, depending on the
initial situation.
- Without Session Border Controller
-
If no session border controller is present, the feature is configured via AMOs and via WBM. In this case, the (v)HG 3500 receives an IP address from the WAN. This IP address is permanently allocated by the service provider.
- With Session Border Controller
-
If a session border controller is being used, it must also be configured. In this case, the (v)HG 3500 has an IP address in the customer LAN, while the session border controller has two IP addresses - one from the customer LAN, and the other from the service provider WAN. The session border controller operates as a router for the (v)HG 3500 in the WAN.
- DNS
-
As you are using Internet telephony and the Internet operates based on names, it is always advisable to use DNS.