lfs-book/chapter07/hosts.xml

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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/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, you have to 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 your computer is to be visible to the Internet (e.g., you have a 
registered domain and a valid block of assigned IP addresses - most of us don't 
have this) you should 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 172.31.0.0
	C     192.168.0.0 through 192.168.255.0</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 as this is a valid registered domain 
address and could cause your domain name server problems).</para>

<para>If you aren't going to use a network card, you still need to 
come up with a FQDN. This is necessary for certain programs to operate
correctly.</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"
# Begin /etc/hosts (no network card version)

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

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

<para>If a network card is to be configured, create the 
<filename>/etc/hosts</filename> file by running:</para>

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

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

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

<para>Of course, the <replaceable>[192.168.1.1]</replaceable> and <replaceable>[&lt;value of HOSTNAME&gt;.example.org]</replaceable>
have to be changed to your liking (or requirements if assigned an IP-address
by a network/system administrator and this machine is planned to be connected
to an existing network).</para>

</sect1>