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