Nat Configuration - D-Link DSL-500 User Manual

DSL-500 ADSL Router User's Guide

NAT Configuration

NAT Configuration Window
Network Address Translation (NAT) is a routing protocol that allows your
network to become a private network that is isolated from, yet connected to the
Internet. It does this by changing the IP address of packets from a global IP
address usable on the Internet to a local IP address usable on your private
network (but not on the Internet) and vice-versa. The Router allows up to 253
host IP addresses.
NAT has two major benefits. First, NAT allows many users to access the Internet
using a single global IP address. This can greatly reduce the costs associated with
Internet access and also helps alleviate the current shortage of Internet IP
addresses. Secondly, the NAT process creates a firewall, which hides your local
network from Internet users, providing a degree of security to your Internet
connection.
To be successfully implemented, NAT should be used only when the majority of
network traffic remains on the local network. In cases where a large percentage
of network traffic is destined for the Internet, NAT can adversely affect the speed
and performance of your Internet connection. Network servers such as ftp
servers, web servers or mail servers should use the port redirection capabilities of
the Router.
NAT will work in conjunction with DHCP and Port Redirection. Thus, if both are
enabled and properly configured, the DHCP server in the DSL-500 will assign
local IP addresses to computers on your network. The Port Redirection feature
allows an administrator to direct specific types of incoming packets to another
server or designated host. For example, a common way to use Port Redirection
would be to direct incoming HTTP packets (through TCP logical port 80) and
redirect them to an HTTP server (conventionally through port 8080).
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