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<div class="titlepage"><div><div><h2 class="title">
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<a name="install-tftp"></a>4.5. Preparing Files for TFTP Net Booting</h2></div></div></div>
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If your machine is connected to a local area network, you may be able
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to boot it over the network from another machine, using TFTP. If you
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intend to boot the installation system from another machine, the
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boot files will need to be placed in specific locations on that machine,
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and the machine configured to support booting of your specific machine.
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You need to set up a TFTP server, and for many machines a DHCP
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server<span class="phrase">, or BOOTP
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<span class="phrase">BOOTP is an IP protocol that
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informs a computer of its IP address and where on the network to obtain
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The DHCP (Dynamic Host Configuration Protocol) is a more flexible,
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backwards-compatible extension of BOOTP.
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Some systems can only be configured via DHCP.
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The Trivial File Transfer Protocol (TFTP) is used to serve the boot
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image to the client. Theoretically, any server, on any platform,
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which implements these protocols, may be used. In the examples in
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this section, we shall provide commands for SunOS 4.x, SunOS 5.x
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(a.k.a. Solaris), and GNU/Linux.
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<div class="note"><table border="0" summary="Note">
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<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td>
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<th align="left">Note</th>
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<tr><td align="left" valign="top"><p>
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For an Ubuntu or Debian server we recommend
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<code class="classname">tftpd-hpa</code>.
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It's written by the same author as the <code class="classname">syslinux</code>
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bootloader and is therefore least likely to cause issues.
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A good alternative is <code class="classname">atftpd</code>.
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<div class="titlepage"><div><div><h3 class="title">
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<a name="dhcpd"></a>4.5.1. Setting up a DHCP server</h3></div></div></div>
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One free software DHCP server is ISC <span class="command"><strong>dhcpd</strong></span>.
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For Ubuntu, the <code class="classname">isc-dhcp-server</code> package is
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recommended. Here is a sample configuration file for it (see
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<code class="filename">/etc/dhcp/dhcpd.conf</code>):
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<div class="informalexample"><pre class="screen">
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option domain-name "example.com";
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option domain-name-servers ns1.example.com;
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option subnet-mask 255.255.255.0;
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default-lease-time 600;
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server-name "servername";
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subnet 192.168.1.0 netmask 255.255.255.0 {
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range 192.168.1.200 192.168.1.253;
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option routers 192.168.1.1;
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filename "/tftpboot.img";
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server-name "servername";
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next-server servername;
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hardware ethernet 01:23:45:67:89:AB;
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fixed-address 192.168.1.90;
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In this example, there is one server
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<em class="replaceable"><code>servername</code></em> which performs all of the work
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of DHCP server, TFTP server, and network gateway. You will almost
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certainly need to change the domain-name options, as well as the
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server name and client hardware address. The
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<em class="replaceable"><code>filename</code></em> option should be the name of the
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file which will be retrieved via TFTP.
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After you have edited the <span class="command"><strong>dhcpd</strong></span> configuration file,
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restart it with <strong class="userinput"><code>/etc/init.d/isc-dhcp-server restart</code></strong>.
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm961"></a>4.5.1.1. Enabling PXE Booting in the DHCP configuration</h4></div></div></div>
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Here is another example for a <code class="filename">dhcp.conf</code> using the
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Pre-boot Execution Environment (PXE) method of TFTP.
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<div class="informalexample"><pre class="screen">
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option domain-name "example.com";
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default-lease-time 600;
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# The next paragraph needs to be modified to fit your case
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subnet 192.168.1.0 netmask 255.255.255.0 {
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range 192.168.1.200 192.168.1.253;
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option broadcast-address 192.168.1.255;
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# the gateway address which can be different
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# (access to the internet for instance)
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option routers 192.168.1.1;
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# indicate the dns you want to use
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option domain-name-servers 192.168.1.3;
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next-server 192.168.1.3;
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# tftp client hardware address
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hardware ethernet 00:10:DC:27:6C:15;
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filename "pxelinux.0";
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Note that for PXE booting, the client filename <code class="filename">pxelinux.0</code>
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is a boot loader, not a kernel image (see <a class="xref" href="ch04s05.html#tftp-images" title="4.5.4. Move TFTP Images Into Place">Section 4.5.4, “Move TFTP Images Into Place”</a>
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<div class="titlepage"><div><div><h3 class="title">
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<a name="tftp-bootp"></a>4.5.2. Setting up a BOOTP server</h3></div></div></div>
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There are two BOOTP servers available for GNU/Linux. The first is CMU
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<span class="command"><strong>bootpd</strong></span>. The other is actually a DHCP server: ISC
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<span class="command"><strong>dhcpd</strong></span>. In Ubuntu these are contained in the
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<code class="classname">bootp</code> and <code class="classname">isc-dhcp-server</code>
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packages respectively.
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To use CMU <span class="command"><strong>bootpd</strong></span>, you must first uncomment (or
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add) the relevant line in <code class="filename">/etc/inetd.conf</code>. On
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Debian or Ubuntu, you can run <strong class="userinput"><code>update-inetd --enable
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bootps</code></strong>, then <strong class="userinput"><code>/etc/init.d/inetd
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reload</code></strong> to do so. Just in case your BOOTP server does not
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run Debian or Ubuntu, the line in question should look like:
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<div class="informalexample"><pre class="screen">
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bootps dgram udp wait root /usr/sbin/bootpd bootpd -i -t 120
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Now, you must create an <code class="filename">/etc/bootptab</code> file. This
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has the same sort of familiar and cryptic format as the good old BSD
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<code class="filename">printcap</code>, <code class="filename">termcap</code>, and
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<code class="filename">disktab</code> files. See the
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<code class="filename">bootptab</code> manual page for more information. For
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CMU <span class="command"><strong>bootpd</strong></span>, you will need to know the hardware
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(MAC) address of the client. Here is an example
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<code class="filename">/etc/bootptab</code>:
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<div class="informalexample"><pre class="screen">
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You will need to change at least the <span class="quote">“<span class="quote">ha</span>”</span> option, which
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specifies the hardware address of the client. The <span class="quote">“<span class="quote">bf</span>”</span>
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option specifies the file a client should retrieve via TFTP; see
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<a class="xref" href="ch04s05.html#tftp-images" title="4.5.4. Move TFTP Images Into Place">Section 4.5.4, “Move TFTP Images Into Place”</a> for more details.
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By contrast, setting up BOOTP with ISC <span class="command"><strong>dhcpd</strong></span> is
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really easy, because it treats BOOTP clients as a moderately special
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case of DHCP clients. Some architectures require a complex
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configuration for booting clients via BOOTP. If yours is one of
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those, read the section <a class="xref" href="ch04s05.html#dhcpd" title="4.5.1. Setting up a DHCP server">Section 4.5.1, “Setting up a DHCP server”</a>. Otherwise you
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will probably be able to get away with simply adding the
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<strong class="userinput"><code>allow bootp</code></strong> directive to the configuration
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block for the subnet containing the client in
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<code class="filename">/etc/dhcp/dhcpd.conf</code>, and restart
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<span class="command"><strong>dhcpd</strong></span> with <strong class="userinput"><code>/etc/init.d/isc-dhcp-server
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restart</code></strong>.
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<div class="titlepage"><div><div><h3 class="title">
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<a name="tftpd"></a>4.5.3. Enabling the TFTP Server</h3></div></div></div>
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To get the TFTP server ready to go, you should first make sure that
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<span class="command"><strong>tftpd</strong></span> is enabled.
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In the case of <code class="classname">tftpd-hpa</code> there are two ways the
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service can be run. It can be started on demand by the system's
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<code class="classname">inetd</code> daemon, or it can be set up to run as an
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independent daemon. Which of these methods is used is selected when the
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package is installed and can be changed by reconfiguring the package.
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<div class="note"><table border="0" summary="Note">
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<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td>
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<th align="left">Note</th>
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<tr><td align="left" valign="top"><p>
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Historically, TFTP servers used <code class="filename">/tftpboot</code> as directory
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to serve images from. However, Ubuntu packages may use other directories
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to comply with the <a class="ulink" href="http://www.pathname.com/fhs/" target="_top">Filesystem Hierarchy
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Standard</a>. For example, <code class="classname">tftpd-hpa</code> by default
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uses <code class="filename">/srv/tftp</code>. You may have to adjust the
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configuration examples in this section accordingly.
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All <span class="command"><strong>in.tftpd</strong></span> alternatives available in Ubuntu should
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log TFTP requests to the system logs by default. Some of them support a
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<strong class="userinput"><code>-v</code></strong> argument to increase verbosity.
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It is recommended to check these log messages in case of boot problems
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as they are a good starting point for diagnosing the cause of errors.
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<div class="titlepage"><div><div><h3 class="title">
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<a name="tftp-images"></a>4.5.4. Move TFTP Images Into Place</h3></div></div></div>
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Next, place the TFTP boot image you need, as found in
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<a class="xref" href="ch04s02.html#where-files" title="4.2.1. Where to Find Installation Images">Section 4.2.1, “Where to Find Installation Images”</a>, in the <span class="command"><strong>tftpd</strong></span>
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boot image directory. You may have to make a link from that
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file to the file which <span class="command"><strong>tftpd</strong></span> will use for booting a
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particular client. Unfortunately, the file name is determined by the
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TFTP client, and there are no strong standards.
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For PXE booting, everything you should need is set up in the
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<code class="filename">netboot/netboot.tar.gz</code> tarball. Simply extract this
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tarball into the <span class="command"><strong>tftpd</strong></span> boot image directory. Make sure
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your dhcp server is configured to pass <code class="filename">pxelinux.0</code>
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to <span class="command"><strong>tftpd</strong></span> as the filename to boot.
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