Added Greg's newly written dhcp chapter to the advanced networking
section. Submitted by: gsutter Reviewed by: jim
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Bill Swingle
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Notes:
svn2git
2020-12-08 03:00:23 +00:00
svn path=/head/; revision=6963
2 changed files with 278 additions and 2 deletions
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@ -1,7 +1,7 @@
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<!--
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The FreeBSD Documentation Project
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$FreeBSD: doc/en_US.ISO_8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.19 2000/02/13 21:14:23 unfurl Exp $
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$FreeBSD: doc/en_US.ISO_8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.20 2000/03/30 23:55:50 jim Exp $
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-->
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<chapter id="advanced-networking">
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@ -1659,6 +1659,144 @@ lrwxr-xr-x 1 root wheel 14 Nov 8 14:27 /usr/lib/libscrypt.so@ -> libscryp
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pretty good place to start looking for possible problems.</para>
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</sect2>
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</sect1>
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<sect1 id="dhcp">
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<title>DHCP</title>
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<para><emphasis>Written by &a.gsutter;, March 2000.</emphasis></para>
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<sect2>
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<title>What is DHCP?</title>
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<para>DHCP, the Dynamic Host Configuration Protocol, describes
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the means by which a system can connect to a network and obtain the
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necessary information for communication upon that network. FreeBSD
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uses the ISC (Internet Software Consortium) DHCP implementation, so
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all implementation-specific information here is for use with the ISC
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distribution.</para>
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</sect2>
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<sect2>
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<title>What this section covers</title>
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<para>This handbook section attempts to describe only the parts
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of the DHCP system that are integrated with FreeBSD;
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consequently, the server portions are not described. The DHCP
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manual pages, in addition to the references below, are useful
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resources.</para>
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</sect2>
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<sect2>
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<title>How it Works</title>
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<para>When dhclient, the DHCP client, is executed on the client
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machine, it begins broadcasting requests for configuration
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information. By default, these requests are on UDP port 68. The
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server replies on UDP 67, giving the client an IP address and
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other relevant network information such as netmask, router, and
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DNS servers. All of this information comes in the form of a DHCP
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"lease" and is only valid for a certain time (configured by the
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DHCP server maintainer). In this manner, stale IP addresses for
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clients no longer connected to the network can be automatically
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reclaimed.</para>
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<para>DHCP clients can obtain a great deal of information from
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the server. An exhaustive list may be found in
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&man.dhcp-options.5;.</para>
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</sect2>
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<sect2>
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<title>FreeBSD Integration</title>
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<para>FreeBSD fully integrates the ISC DHCP client,
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<command>dhclient</command>. DHCP client support is provided
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within both the installer and the base system, obviating the need
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for detailed knowledge of network configurations on any network
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that runs a DHCP server. <command>dhclient</command> has been
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included in all FreeBSD distributions since 3.2.</para>
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<para>DHCP is supported by <application>sysinstall</application>.
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When configuring a network interface within sysinstall,
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the first question asked is, "Do you want to try dhcp
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configuration of this interface?" Answering affirmatively will
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execute dhclient, and if successful, will fill in the network
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configuration information automatically.</para>
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<para>To have your system use DHCP to obtain network information
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upon startup, edit your <filename>/etc/rc.conf</filename> to
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include the following:</para>
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<programlisting>
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ifconfig_fxp0="DHCP"
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</programlisting>
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<note>
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<para>Be sure to replace <literal>fxp0</literal> with the
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designation for the interface that you wish to dynamically
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configure.</para>
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</note>
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<para>If you are using a different location for
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<command>dhclient</command>, or if you wish to pass additional
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flags to <command>dhclient</command>, also include the
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following (editing as necessary):</para>
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<programlisting>
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dhcp_program="/sbin/dhclient"
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dhcp_flags=""
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</programlisting>
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<para>The DHCP server, <command>dhcpd</command>, is included
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as part of the <literal>isc-dhcp2</literal> port in the ports
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collection. This port contains the full ISC DHCP distribution,
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consisting of client, server, relay agent and documentation.
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</para>
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</sect2>
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<sect2>
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<title>Files</title>
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<itemizedlist>
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<listitem><para><filename>/etc/dhclient.conf</filename></para>
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<para><command>dhclient</command> requires a configuration file,
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<filename>/etc/dhclient.conf</filename>. Typically the file
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contains only comments, the defaults being reasonably sane. This
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configuration file is described by the &man.dhclient.conf.5;
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man page.</para>
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</listitem>
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<listitem><para><filename>/sbin/dhclient</filename></para>
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<para><command>dhclient</command> is statically linked and
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resides in <filename>/sbin</filename>. The &man.dhclient.8;
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manual page gives more information about
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<command>dhclient</command>.</para>
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</listitem>
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<listitem><para><filename>/sbin/dhclient-script</filename></para>
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<para><command>dhclient-script</command> is the FreeBSD-specific
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DHCP client configuration script. It is described in
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&man.dhclient-script.8;, but should not need any user
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modification to function properly.</para>
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</listitem>
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<listitem><para><filename>/var/db/dhclient.leases</filename></para>
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<para>The DHCP client keeps a database of valid leases in this
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file, which is written as a log. &man.dhclient.leases.5;
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gives a slightly longer description.</para>
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</listitem>
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</itemizedlist>
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</sect2>
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<sect2>
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<title>Further Reading</title>
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<para>The DHCP protocol is fully described in
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<ulink url="http://www.freesoft.org/CIE/RFC/2131/">RFC 2131</ulink>.
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An informational resource has also been set up at
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<ulink url="http://www.dhcp.org/">dhcp.org</ulink>.</para>
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</sect2>
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</sect1>
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</chapter>
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<!--
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@ -1,7 +1,7 @@
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<!--
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The FreeBSD Documentation Project
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||||
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$FreeBSD: doc/en_US.ISO_8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.19 2000/02/13 21:14:23 unfurl Exp $
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$FreeBSD: doc/en_US.ISO_8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.20 2000/03/30 23:55:50 jim Exp $
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-->
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<chapter id="advanced-networking">
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@ -1659,6 +1659,144 @@ lrwxr-xr-x 1 root wheel 14 Nov 8 14:27 /usr/lib/libscrypt.so@ -> libscryp
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pretty good place to start looking for possible problems.</para>
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</sect2>
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</sect1>
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<sect1 id="dhcp">
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<title>DHCP</title>
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<para><emphasis>Written by &a.gsutter;, March 2000.</emphasis></para>
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<sect2>
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<title>What is DHCP?</title>
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<para>DHCP, the Dynamic Host Configuration Protocol, describes
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the means by which a system can connect to a network and obtain the
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necessary information for communication upon that network. FreeBSD
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uses the ISC (Internet Software Consortium) DHCP implementation, so
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all implementation-specific information here is for use with the ISC
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distribution.</para>
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</sect2>
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<sect2>
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<title>What this section covers</title>
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<para>This handbook section attempts to describe only the parts
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of the DHCP system that are integrated with FreeBSD;
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consequently, the server portions are not described. The DHCP
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manual pages, in addition to the references below, are useful
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resources.</para>
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</sect2>
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<sect2>
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<title>How it Works</title>
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<para>When dhclient, the DHCP client, is executed on the client
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machine, it begins broadcasting requests for configuration
|
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information. By default, these requests are on UDP port 68. The
|
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server replies on UDP 67, giving the client an IP address and
|
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other relevant network information such as netmask, router, and
|
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DNS servers. All of this information comes in the form of a DHCP
|
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"lease" and is only valid for a certain time (configured by the
|
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DHCP server maintainer). In this manner, stale IP addresses for
|
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clients no longer connected to the network can be automatically
|
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reclaimed.</para>
|
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<para>DHCP clients can obtain a great deal of information from
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the server. An exhaustive list may be found in
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&man.dhcp-options.5;.</para>
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</sect2>
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<sect2>
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<title>FreeBSD Integration</title>
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<para>FreeBSD fully integrates the ISC DHCP client,
|
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<command>dhclient</command>. DHCP client support is provided
|
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within both the installer and the base system, obviating the need
|
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for detailed knowledge of network configurations on any network
|
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that runs a DHCP server. <command>dhclient</command> has been
|
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included in all FreeBSD distributions since 3.2.</para>
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<para>DHCP is supported by <application>sysinstall</application>.
|
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When configuring a network interface within sysinstall,
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the first question asked is, "Do you want to try dhcp
|
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configuration of this interface?" Answering affirmatively will
|
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execute dhclient, and if successful, will fill in the network
|
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configuration information automatically.</para>
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<para>To have your system use DHCP to obtain network information
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upon startup, edit your <filename>/etc/rc.conf</filename> to
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include the following:</para>
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<programlisting>
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ifconfig_fxp0="DHCP"
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</programlisting>
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<note>
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<para>Be sure to replace <literal>fxp0</literal> with the
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designation for the interface that you wish to dynamically
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configure.</para>
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</note>
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<para>If you are using a different location for
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<command>dhclient</command>, or if you wish to pass additional
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flags to <command>dhclient</command>, also include the
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following (editing as necessary):</para>
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<programlisting>
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dhcp_program="/sbin/dhclient"
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dhcp_flags=""
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</programlisting>
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<para>The DHCP server, <command>dhcpd</command>, is included
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as part of the <literal>isc-dhcp2</literal> port in the ports
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collection. This port contains the full ISC DHCP distribution,
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consisting of client, server, relay agent and documentation.
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</para>
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</sect2>
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<sect2>
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<title>Files</title>
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<itemizedlist>
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<listitem><para><filename>/etc/dhclient.conf</filename></para>
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<para><command>dhclient</command> requires a configuration file,
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<filename>/etc/dhclient.conf</filename>. Typically the file
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contains only comments, the defaults being reasonably sane. This
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configuration file is described by the &man.dhclient.conf.5;
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man page.</para>
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</listitem>
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<listitem><para><filename>/sbin/dhclient</filename></para>
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<para><command>dhclient</command> is statically linked and
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resides in <filename>/sbin</filename>. The &man.dhclient.8;
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manual page gives more information about
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<command>dhclient</command>.</para>
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</listitem>
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<listitem><para><filename>/sbin/dhclient-script</filename></para>
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<para><command>dhclient-script</command> is the FreeBSD-specific
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DHCP client configuration script. It is described in
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&man.dhclient-script.8;, but should not need any user
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modification to function properly.</para>
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</listitem>
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<listitem><para><filename>/var/db/dhclient.leases</filename></para>
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<para>The DHCP client keeps a database of valid leases in this
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file, which is written as a log. &man.dhclient.leases.5;
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gives a slightly longer description.</para>
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</listitem>
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</itemizedlist>
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</sect2>
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<sect2>
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<title>Further Reading</title>
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<para>The DHCP protocol is fully described in
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<ulink url="http://www.freesoft.org/CIE/RFC/2131/">RFC 2131</ulink>.
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An informational resource has also been set up at
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<ulink url="http://www.dhcp.org/">dhcp.org</ulink>.</para>
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</sect2>
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</sect1>
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||||
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||||
</chapter>
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||||
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||||
<!--
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||||
|
|
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