74 lines
4.2 KiB
HTML
74 lines
4.2 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html 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="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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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Secure the DHCP server" />
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<meta name="abstract" content="This article provides recommendations for securing the DHCP server." />
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<meta name="description" content="This article provides recommendations for securing the DHCP server." />
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<meta name="DC.Relation" scheme="URI" content="rzamvtcpdhcp.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="tcpsecdhcp" />
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<meta name="DC.Language" 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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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Secure the DHCP server</title>
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</head>
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<body id="tcpsecdhcp"><a name="tcpsecdhcp"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Secure the DHCP server</h1>
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<div><p>This article provides recommendations for securing the DHCP server.</p>
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<p>Following are security considerations when you choose to run DHCP on your
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system:</p>
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<ul><li>Restrict the number of users who have authority to administer DHCP. Administering
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DHCP requires the following authority:<ul><li>*IOSYSCFG special authority</li>
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<li>*RW authority to the following files:<pre>/QIBM/UserData/OS400/DHCP/dhcpsd.cfg
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/QIBM/UserData/OS400/DHCP/dhcprd.cfg</pre>
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</li>
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</ul>
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</li>
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<li>Evaluate how physically accessible your LAN is. Could an outsider easily
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walk into your location with a laptop and physically connect it to your LAN?
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If this is an exposure, DHCP provides the capability to create a list of clients
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(hardware addresses) that the DHCP server will configure. When you use this
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feature, you remove some of the productivity benefit that DHCP provides to
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your network administrators. However, you prevent the system from configuring
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unknown workstations.</li>
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<li>If possible, use a pool of IP addresses that is reusable (not architected
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for the Internet). This helps prevent a workstation from outside your network
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from gaining usable configuration information from the server. </li>
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<li>Use the DHCP exit points if you need additional security protection. Following
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is an overview of the exit points and their capabilities. <dl><dt class="dlterm">Port entry</dt>
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<dd>The system calls your exit program whenever it reads a data packet from
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port 67 (the DHCP port). Your exit program receives the full data packet.
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It can decide whether the system should process or discard the packet. You
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can use this exit point when existing DHCP screening features are not sufficient
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for your needs.</dd>
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<dt class="dlterm">Address assignment</dt>
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<dd>The system calls your exit program whenever DHCP formally assigns an address
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to a client.</dd>
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<dt class="dlterm">Address release</dt>
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<dd>The system calls your exit program whenever DHCP formally releases an
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address and places it back in the address pool.</dd>
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</dl>
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</li>
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</ul>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzamvtcpdhcp.htm" title="These topics discuss methods for securing the DHCP server for authorized users and preventing access to the DHCP server.">Security considerations for using DHCP server</a></div>
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</div>
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</div>
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</body>
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</html>
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