ZyXEL Communications NBG-416N - 11.2 What You Can Do

Chapter 11 Network Address Translation (NAT)
NBG-416N User’s Guide
102
For more information on IP address translation, refer to RFC 1631, The IP Network
Address Translator (NAT).
Note: You must create a firewall rule in addition to setting up NAT, to allow traffic from
the WAN to be forwarded through the NBG-416N.
11.2 What You Can Do
•Use the General screen to enable NAT and set a default server (Section 11.3 on
page 104).
•Use the Application screen to change your NBG-416N’s port forwarding
settings (Section 11.4 on page 105).
11.2.1 What You Need To Know
The following terms and concepts may help as you read through this chapter.
Inside/Outside
This denotes where a host is located relative to the NBG-416N, for example, the
computers of your subscribers are the inside hosts, while the web servers on the
Internet are the outside hosts.
Global/Local
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 40 NAT Definitions
ITEM DESCRIPTION
Inside This refers to the host on the LAN.
Outside This refers to the host on the WAN.