If a network card is to be configured, decide on the IP address,
fully-qualified domain name (FQDN), and possible aliases for use in
the /etc/hosts file. The syntax is:
IP_address myhost.example.org aliases
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—most users do not have this), make sure that the IP address is in the private network IP address range. Valid ranges are:
Private Network Address Range Normal Prefix
10.0.0.1 - 10.255.255.254 8
172.x.0.1 - 172.x.255.254 16
192.168.y.1 - 192.168.y.254 24
x can be any number in the range 16-31. y can be any number in the range 0-255.
A valid private IP address could be 192.168.1.1. A valid FQDN for this IP could be lfs.example.org.
Even if not using a network card, a valid FQDN is still required. This is necessary for certain programs to operate correctly.
Create the /etc/hosts file by running:
cat > /etc/hosts << "EOF"
# Begin /etc/hosts (network card version)
127.0.0.1 localhost
<192.168.1.1> <HOSTNAME.example.org> [alias1] [alias2 ...]
# End /etc/hosts (network card version)
EOF
The <192.168.1.1> and
<HOSTNAME.example.org> values
need to be changed for specific uses or requirements (if assigned an
IP address by a network/system administrator and the machine will be
connected to an existing network). The optional alias name(s) can be
omitted.
If a network card is not going to be configured, create the
/etc/hosts file by running:
cat > /etc/hosts << "EOF"
# Begin /etc/hosts (no network card version)
127.0.0.1 <HOSTNAME.example.org> <HOSTNAME> localhost
# End /etc/hosts (no network card version)
EOF