hosts(4)                                                              hosts(4)


NAME
     hosts - hostname-address database

DESCRIPTION
     The /etc/hosts file contains information regarding the known hosts on the
     network.  For each host a single line should be present with the
     following information:

          +  Internet address

          +  official hostname

          +  aliases (optional)

     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 that search the file.  For example,

          192.0.2.2   iris.widgets.com   iris

     This file must include entries for all of the machine's network
     interfaces, the localhost address and a few important machines on the
     local network.  ifconfig(1M) uses this file when assigning addresses to
     the network interfaces during system initialization.

     By default, this file is used by gethostbyname(3N) and gethostbyaddr(3N)
     only when the NIS or the Berkeley Internet name server (named(1M)) are
     not enabled.  The system can be configured to use NIS, named, and/or this
     file, as described in resolver(4).

     If the host is not connected to any network, the file should contain an
     entry defining the hostname as an alias for the localhost entry.  For
     example, if the hostname is IRIS, the /etc/hosts file should contain this
     line:

          127.1   localhost   IRIS

     Sites connected to the Internet should configure the system to use the
     name server.  This file can be created from the official host database
     maintained at the Network Information Center (NIC), though local changes
     may be required to bring it up to date regarding unofficial aliases
     and/or unknown hosts.  The host database maintained at NIC is incomplete.

     Network addresses are specified in the conventional dot (.) notation
     using the inet_addr() routine from the Internet address manipulation
     library, inet(3N).  Legal hostnames can contain any alphanumeric
     character, the minus sign (-) and period (.).  Periods are not part of
     the name but serve to separate components of a domain-style name.


FILES
     /etc/hosts

SEE ALSO
     ifconfig(1M), named(1M), gethostbyname(3N), resolver(4), sys_id(4),
     hostname(5).


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