11

Network Address Translation (NAT)

11.1 Overview

This chapter discusses how to configure NAT on the AMG1312-T Series. 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 to a different IP address known within another network.

11.1.1What You Can Do in the NAT Screens

•Use the General screen (Section 11.2 on page 148) to activate/deactivate NAT for the default WAN connection (PVC0).

•Use the Port Forwarding screen (Section 11.3 on page 149) to configure forward incoming service requests to the server(s) on your local network.

•Use the DMZ screen to configure a default server (Section 11.4 on page 152).

•Use the ALG screen to enable and disable the NAT and SIP (VoIP) ALG in the AMG1312-T Series Section 11.5 on page 152).

11.1.2What You Need To Know About NAT

Inside/Outside

Inside/outside denotes where a host is located relative to the AMG1312-T Series, for example, the computers of your subscribers are the inside hosts, while the web servers on the Internet are the outside hosts.

Global/Local

Global/local 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.

NAT

In the simplest form, NAT changes the source IP address in a packet received from a subscriber (the inside local address) to another (the inside global address) before forwarding the packet to the WAN side. When the response comes back, NAT translates the destination address (the inside global address) back to the inside local address before forwarding it to the original inside host.

 

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AMG1312-T Series User’s Guide