lfs-book/chapter07/hosts.xml

<sect1 id="ch07-hosts">
<title>Creating the /etc/hosts file</title>

<para>
If a network card is to be configured, a user has to decide on the
IP-address, FQDN and possible aliases for use in the /etc/hosts file. An
example is:
</para>

<para>
<screen>
&lt;my-IP&gt; myhost.mydomain.org aliases
</screen>
</para>

<para>
It should made sure that the IP-address is in the private network
IP-address range. Valid ranges are:
</para>

<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>

<para>
A valid IP address could be 192.168.1.1. A valid FQDN for this IP could
be www.linuxfromscratch.org
</para>

<para>
If a user is not going to use a network card, he still needs to come up with a
FQDN. This is necessary for programs like Sendmail to operate correctly (in
fact; Sendmail won't run when it can't determine the FQDN).
</para>

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

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

127.0.0.1 www.mydomain.com &lt;value of HOSTNAME&gt; localhost

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

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

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

127.0.0.1 localhost.localdomain localhost
192.168.1.1 www.mydomain.org &lt;value of HOSTNAME&gt;

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

<para>
Of course, the 192.168.1.1 and www.mydomain.org have to be changed to the 
users 
liking (or requirements if assigned an IP-address by a network/system
administrator and this machine is planned to be connected to that network).
</para>

</sect1>