<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><my-IP> 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 > /etc/hosts << "EOF"</userinput> # Begin /etc/hosts (no network card version) 127.0.0.1 www.mydomain.com <value of HOSTNAME> 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 > /etc/hosts << "EOF"</userinput> # Begin /etc/hosts (network card version) 127.0.0.1 localhost.localdomain localhost 192.168.1.1 www.mydomain.org <value of HOSTNAME> # 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>