freebsd man page for hosts

HOSTS(5)						      BSD File Formats Manual							  HOSTS(5)

NAME
     hosts -- host name data base

DESCRIPTION
     The hosts file contains information regarding the known hosts on the network.  It can be used in conjunction with DNS, and the NIS maps
     `hosts.byaddr' and `hosts.byname', as controlled by nsswitch.conf(5).  For each host a single line should be present with the following
     information:

	   Internet address
	   official host name
	   aliases

     Items are separated by any number of blanks and/or tab characters.  A ``#'' indicates the beginning of a comment; characters up to the end of
     the line are not interpreted by routines which search the file.

     This file provides a backup used when the name server is not running.  For the name server, it is suggested that only a few addresses be
     included in this file.  These include addresses for the local interfaces that ifconfig(8) needs at boot time and a few machines on the local
     network.

     This file may be created from the official host data base maintained at the Network Information Control Center (NIC), though local changes
     may be required to bring it up to date regarding unofficial aliases and/or unknown hosts.	As the data base maintained at NIC is incomplete,
     use of the name server is recommended for sites on the DARPA Internet.

     Network addresses are specified in the conventional ``.'' (dot) notation using the inet_addr(3) routine from the Internet address manipula-
     tion library, inet(3).  Host names may contain any printable character other than a field delimiter, newline, or comment character.

FILES
     /etc/hosts  The hosts file resides in /etc.

SEE ALSO
     gethostbyname(3), nsswitch.conf(5), ifconfig(8)

     Name Server Operations Guide for BIND.

HISTORY
     The hosts file format appeared in 4.2BSD.

BSD
								 December 25, 2013							       BSD