ZyXEL nbg-5715 Guia Do Utilizador
NBG5715 User’s Guide
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H A P T E R
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NAT
14.1 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.
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).
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 NBG5715. 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 NBG5715, which is
192.168.1.1.
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 NBG5715, which is
192.168.1.1.
Figure 60
NAT Example
This chapter discusses how to configure NAT on the NBG5715.
Note: You must create a firewall rule in addition to setting up NAT, to allow traffic from
the WAN to be forwarded through the NBG5715.
14.1.1 What You Can Do in this Chapter
• Use the General screen to enable NAT and set a default server (
).
• Use the Port Forwarding screen to forward incoming service requests to the server(s) on your
local network (
A: 192.168.1.33
B: 192.168.1.34
C: 192.168.1.35
IP address
192.168.1.1
WAN
LAN
assigned by ISP
FTP, Telnet, SNMP
Port 80
Ports 21 to 25