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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       In  modern  systems,  even though the host table has been superseded by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

       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.