ZyXEL nbg-4615 Guida Utente

Chapter 19 NAT

NBG4615 User’s Guide

Note: You must create a firewall rule in addition to setting up NAT, to allow traffic from 

the WAN to be forwarded through the NBG4615.

• Use  the  General screen to enable NAT and set a default server (

• Use  the  Application screen to change your NBG4615’s port forwarding settings 

(

).

• Use  the  Advanced screen to change your NBG4615’s trigger port settings 

(

).

The following terms and concepts may help as you read through this chapter.

This denotes where a host is located relative to the NBG4615, for example, the 
computers of your subscribers are the inside hosts, while the web servers on the 
Internet are the outside hosts. 

This denotes the IP address of a host in a packet as the packet traverses a router, 
for example, the local address refers to the IP address of a host when the packet 
is in the local network, while the global address refers to the IP address of the 
host when the same packet is traveling in the WAN side. 

Note: Inside/outside refers to the location of a host, while global/local refers to the IP 

address of a host used in a packet. 

An inside local address (ILA) is the IP address of an inside host in a packet when 
the packet is still in the local network, while an inside global address (IGA) is the 
IP address of the same inside host when the packet is on the WAN side. The 
following table summarizes this information.

Table 64   NAT Definitions

Inside

This refers to the host on the LAN.

Outside

This refers to the host on the WAN.