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Lesson 2Introducing the features of NAT
ObjectiveList the key features of the NAT protocol and introduce NAT as a solution for Internet Connectivity

Introducing the features of NAT

NAT connects private networks to the Internet while also protecting the private network resources. To design a strategy for providing Internet connectivity by using NAT, you must:
  1. Establish the design requirements for a NAT solution
  2. Identify how the features provided by NAT support the Internet connectivity design requirements

To ensure an effective Internet-connectivity solution, you need to understand how the features of NAT support the organization's connectivity requirements. NAT is one of the protocols supported by Routing and Remote Access in Windows® 2000; therefore, to use NAT, you must install\ the Routing and Remote Access Service (RRAS) on servers that will provide the NAT solution.

The features of NAT

The following Slideshow illustrates the key features of the NAT protocol.
  1. The network address translation feature of NAT secures the private network by hiding the private network addresses from Internet-based users
  2. Internet hosts cannot directly connect to machines that use private IP addresses
  3. Network address translation allows one or more public addresses to be translated to the private Internet Protocol (IP)
  4. The NAT server should have a single network card connected to a single internal, private network, and may have multiple network cards connected to public networks.
  5. Network Address translation is inherent in NAT and necessitates the use of private addressing on internal network client accessing the Internet via the NAT server.
  6. When a public address exists for each computer on the private network, use IP routing as provided in Routing and Remote Access.
  7. The automatic IP-address assignment feature of NAT supplies the IP configuration to client computers on the private network.
  8. The name resolution feature of NAT uses DNS proxies to forward requests for name resolution. The DNS proxy forwards the name resolution requests to the DNS server.
  9. The NAT server sends clients requests to the appropriate DNS servers on the private network or across the internet, depending on how you have configured the NAT server.
  10. If you want to host resources on the internal network to be available to internet users, a specific port can be configure that will forward request from Internet-based hosts to access those resources on your internal network.
  11. Finally, the NAT server forwards requests from Internet-based users to the computers on the private network that manage a resource such as the internal web or FTP server.

NAT Features

Integrating NAT into existing networks

When integrating NAT into existing networks, consider that it supports automatic IP configuration of client computers that use DHCP for configuration. Computers on the internal network that are configured as DHCP clients can have their IP addressing information configured by the NAT server's DHCP Allocator.
If you choose to enable the NAT server's DHCP Allocator, you must not have any other DHCP servers on the internal network. The non-NAT DHCP server may assign IP-address information that would prevent the DHCP client computers from properly connecting to the NAT server.
It is important to remember that NAT supports only the IP protocol, not any other routable protocols, such as Internetwork Package Exchange/Sequenced Packet Exchange (IPX/SPX). If you wish to access the Internet via IPX/SPX, you must use a Proxy Server to perform the protocol translation.
The next lesson will detail the protocols that are not supported by NAT.

Nat Review - Quiz

Click the Quiz link below to take a short quiz on the features of NAT.
Nat Review - Quiz