NR2101 User’s Guide
80
C
HAPTER
8
NAT
8.1 Overview
NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP address of a host in a
packet. For example, the source address of an outgoing packet, used within one network is changed to
a different IP address known within another network.
The figure below is a simple illustration of a NAT network. You want to assign ports 21-25 to one FTP, Telnet
and SMTP server (
A
in the example), port 80 to another (
B
in the example) and assign a default server IP
address of 192.168.1.35 to a third (
C
in the example).
You assign the LAN IP addresses to the devices (
A
to
D
) connected to your NR2101. The ISP assigns the
WAN IP address. The NAT network appears as a single host on the Internet. All traffic coming from
A
to
D
going out to the Internet use the IP address of the NR2101, which is 192.168.1.1.
Figure 86
NAT Example
Note: You must create a firewall rule in addition to setting up NAT, to allow traffic from the
WAN to be forwarded through the NR2101.
8.1.1 What You Can Do
• Use the
NAT Settings
screen to configure your NR2101’s VPN pass-through and port forwarding settings
