ZyXEL NBG-417N Manual De Usuario
NBG-417N User’s Guide
117
C
H A P T E R
11
Network Address Translation
(NAT)
11.1 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.
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).
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 NBG-
417N. 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 NBG-417N, which is 192.168.1.1.
417N. 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 NBG-417N, which is 192.168.1.1.
Figure 65 NAT Example
This chapter discusses how to configure NAT on the NBG-417N.
A: 192.168.1.33
B: 192.168.1.34
C: 192.168.1.35
IP address
192.168.1.1
NBG-417N
WAN
LAN
assigned by ISP
FTP, Telnet, SNMP
Port 80
Ports 21 to 25