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 follow­
       ing information:

              IP_address canonical_hostname aliases

       Each  field  of  the  entry  is 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 any printable character other  than
       a  field delimiter, newline, or comment 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 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       superseded by DNS, it is still widely used for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 advan­
              tage.

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 created 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),  host­
       name(7), named(8), Internet RFC 952

AUTHOR

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