Network Address Translation (NAT) translates a private IP address on the Local Area Network (LAN) to a public (WAN) IP address, and translates a public (WAN) IP address to a private LAN IP address. This article describes how to reserve a range of ports on a SPA8000. The range of ports, which are identified as reserved ports, are designated to not be used for Network Address Translation (NAT).
Note: If port forwarding is set on a reserved port, then the port forwarding for that specific port is cancelled.
Step 1. Log in to the web configuration utility as an administrator and choose Advanced > Network > Application. The Application page opens:
Step 2. Under the System Reserved Ports Range area enter the starting port in the Starting Port field. This is starting port of the reserved ports range. This port range defines the TCP/UDP ports used by the applications that operate on the phone adapter.
Note: The default starting port is 50000.
Step 3. From the Num of Ports Reserved drop-down list choose the number of ports to reserve. This gives the total number of ports reserved. Ports are reserved to provide particular services to a host.
Note: The default value for Num of Ports Reserved is 256.
Step 4. Click Submit All Changes to save the configuration.