lfs-book/chapter07/hosts.xml

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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../general.ent">
  %general-entities;
]>
<sect1 id="ch-scripts-hosts">
<title>Creating the /etc/hosts File</title>
<?dbhtml filename="hosts.html"?>

<indexterm zone="ch-scripts-hosts"><primary sortas="e-/etc/hosts">/etc/hosts</primary></indexterm>

<indexterm zone="ch-scripts-hosts">
<primary sortas="d-localnet">localnet</primary>
<secondary>/etc/hosts</secondary></indexterm>

<indexterm zone="ch-scripts-hosts">
<primary sortas="d-network">network</primary>
<secondary>/etc/hosts</secondary></indexterm>

<para>If a network card is to be configured, decide on the IP address,
FQDN, and possible aliases for use in the
<filename>/etc/hosts</filename> file. The syntax is:</para>

<screen>&lt;IP address&gt; myhost.example.org aliases</screen>

<para>Unless the computer is to be visible to the Internet (i.e.,
there is a registered domain and a valid block of assigned IP
addresses&mdash;most users do not have this), make sure that the IP
address is in the private network IP address range. Valid ranges
are:</para>

<screen>	Class Networks
	A     10.0.0.0
	B     172.16.0.0 through 172.31.0.255
	C     192.168.0.0 through 192.168.255.255</screen>

<para>A valid IP address could be 192.168.1.1. A valid FQDN for this
IP could be www.linuxfromscratch.org (not recommended because this is
a valid registered domain address and could cause domain name server
issues).</para>

<para>Even if not using a network card, an FQDN is still required.
This is necessary for certain programs to operate correctly.</para>

<para>Create the  <filename>/etc/hosts</filename> file by running:</para>

<screen><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
<literal># Begin /etc/hosts (network card version)

127.0.0.1 localhost
<replaceable>[192.168.1.1]</replaceable> <replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable> <replaceable>[HOSTNAME]</replaceable>

# End /etc/hosts (network card version)</literal>
EOF</userinput></screen>

<para>The <replaceable>[192.168.1.1]</replaceable> and
<replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable>
values need to be changed for specific users or requirements (if
assigned an IP address by a network/system administrator and the
machine will be connected to an existing network).</para>

<para>If a network card is not going to be configured, create the
<filename>/etc/hosts</filename> file by running:</para>

<screen><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
<literal># Begin /etc/hosts (no network card version)

127.0.0.1 <replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable> <replaceable>[HOSTNAME]</replaceable> localhost

# End /etc/hosts (no network card version)</literal>
EOF</userinput></screen>

</sect1>