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       hosts - The static table lookup for host names




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       In modern systems, even though the host table has been superseded  by  DNS,  it  is  still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

              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       localhost  foo  bar      master


       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.




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


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