HOSTS(5)						      Debian GNU/Linux manual							  HOSTS(5)

NAME

       hosts - The static table lookup for host names

SYNOPSIS

       /etc/hosts

DESCRIPTION

       This  manual page describes the format of the /etc/hosts file. This file is a simple text file that associates IP addresses with hostnames,
       one line per IP address. For each host a single line should be present with the following information:

	      IP_address canonical_hostname aliases

       Fields of the entry are separated by any number of blanks and/or tab characters. Text from a "#" character until the end of the line  is  a
       comment,  and is ignored.  Host names may contain only alphanumeric characters, minus signs ("-"), and periods (".").  They must begin with
       an alphabetic character and end with an alphanumeric character.	Aliases provide for name changes, alternate spellings, shorter	hostnames,
       or generic hostnames (for example, localhost).  The format of the host table is described in RFC 952.

       The  Berkeley  Internet	Name  Domain  (BIND)  Server  implements  the  Internet  name server for UNIX systems. It augments or replaces the
       /etc/hosts file or host name lookup, and frees a host from relying on /etc/hosts being up to date and complete.

       In modern systems, even though the host table has been superseded by DNS, it is still widely used for:

       bootstrapping
	      Most systems have a small host table containing the name and address information for important hosts on the local network.  This	is
	      useful when DNS is not running, for example during system bootup.

       NIS    Sites  that use NIS use the host table as input to the NIS host database. Even though NIS can be used with DNS, most NIS sites still
	      use the host table with an entry for all local hosts as a backup.

       isolated nodes
	      Very small sites that are isolated from the network use the host table instead of DNS. If the local information rarely changes,  and
	      the network is not connected to the Internet, DNS offers little advantage.

EXAMPLE

	127.0.0.1	localhost
	192.168.1.10	foo.mydomain.org  foo
	192.168.1.13	bar.mydomain.org  bar
	216.234.231.5	master.debian.org      master
	205.230.163.103 www.opensource.org

HISTORICAL NOTE

       Before the advent of DNS, the host table was the only way of resolving hostnames on the fledgling Internet. Indeed, this file could be cre-
       ated from the official host data base maintained at the Network Information Control Center (NIC), though local changes were often  required
       to  bring it up to date regarding unofficial aliases and/or unknown hosts.  The NIC no longer maintains the hosts.txt files, though looking
       around at the time of writing (circa 2000), there are historical hosts.txt files on the WWW. I just found three, from 92, 94, and 95.

FILES

       /etc/hosts

SEE ALSO

       hostname(1) resolver(3), resolver(5), hosts(5), hostname(7), named(8), Internet RFC 952

AUTHOR

       This manual page was written by Manoj Srivastava <srivasta@debian.org>, for the Debian GNU/Linux system.

Debian								    2002-06-16								  HOSTS(5)