70 lines
4.0 KiB
HTML
70 lines
4.0 KiB
HTML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="dc.language" scheme="rfc1766" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<meta name="dc.date" scheme="iso8601" content="2005-09-06" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow"/>
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<title>Network address translation (NAT)</title>
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<link rel="stylesheet" type="text/css" href="ibmidwb.css" />
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<link rel="stylesheet" type="text/css" href="ic.css" />
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</head>
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<body>
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<a id="Top_Of_Page" name="Top_Of_Page"></a><!-- Java sync-link -->
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<script language = "Javascript" src = "../rzahg/synch.js" type="text/javascript"></script>
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<a name="icnat"></a>
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<h3 id="icnat">Network address translation (NAT)</h3>
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<p>Network Address Translation (NAT) translates internal or private IP addresses
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to public or globally routable IP addresses and also translates ports. In
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order for the Universal Connection to connect to IBM® through a NAT, you must enable NAT traversal,
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as described in the <a href="../rzaja/rzajaudpencap.htm">NAT compatible IPSec</a> topic,
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so that the translation of the address does not break the encrypted data flow.
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The Universal Connection wizard automatically enables this technology.</p>
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<p>NAT provides the following advantages:</p>
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<ul>
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<li>NAT saves public IP addresses. Because a client only needs a public IP
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address when it is communicating with the Internet, the pool of globally routable
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IP addresses can be shared with other clients. Therefore, you need fewer public
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IP addresses than the actual number of internal clients that need access to
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the public network if you use NAT. When your private IP address sends traffic
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through the NAT, this software translates the private address to the public
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address. This feature and the ability to translate both the IP address and
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port (NAT port mapping) make it possible, in many NAT implementations, to
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require only one public IP address.</li>
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<li>NAT hides the internal network's IP addresses.</li>
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<li>It simplifies routing. Since internal hosts are assigned IP addresses
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from the internal network, other internal systems can access them without
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special routes or routers. The same hosts are accessed from the public network
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through globally routable IP addresses translated by NAT.</li>
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<li>NAT is transparent to the client and, therefore, allows you to support
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a wider range of clients.</li>
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<li>NAT supports a wide range of services with a few exceptions. Any application
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that carries and uses the IP address inside the application does not work
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through NAT.</li>
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<li>NAT consumes fewer computer resources and is more efficient than using
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SOCKS and application proxy servers.</li>
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<li>The Universal Connection can flow through NAT.</li></ul>
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<p>Some disadvantages of NAT include the following:</p>
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<ul>
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<li>NAT provides minimum logging services.</li>
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<li>You must enable IP forwarding before you can use NAT to make an Internet
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connection.</li>
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<li>NAT is not as adept as either the SOCKS or application proxy servers in
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detecting attacks.</li>
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<li>NAT can break certain applications, or make these applications more difficult
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to run.</li></ul>
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<a id="Bot_Of_Page" name="Bot_Of_Page"></a>
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</body>
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</html>
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