4.3BSD/etc/hosts

#
# Host Database
# This file should contain the addresses and aliases
# for local hosts that share this file.
# It is used only for "ifconfig" and other operations
# before the nameserver is started.
#
# Choose a distinguished local network address for localhost.
#
0.1		localhost localhost.my.domain
#
# Imaginary network.
0.2		myname.my.domain myname
0.3		myfriend.my.domain myfriend