If a network card is to be configured, you have to decide on the IP-address, FQDN and possible aliases for use in the /etc/hosts file. An example is: <my-IP> myhost.mydomain.org aliases You should made sure that the IP-address is in the private network IP-address range. Valid ranges are: 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 A valid IP address could be 192.168.1.1. A valid FQDN for this IP could be www.linuxfromscratch.org If you aren't going to use a network card, you still need 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). If a network card is not going to be configured, a new file /etc/hosts is created by running: cat > /etc/hosts << "EOF" # 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) EOF If a network card is to be configured, a new file /etc/hosts is created by running: cat > /etc/hosts << "EOF" # 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) EOF Of course, the 192.168.1.1 and www.mydomain.org 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 that network).