hosts(SFF)                      19 June 1992                      hosts(SFF)


 Name

    hosts - list of hosts on network

 Description

    The file /etc/hosts is a list of hosts that share the network, including
    the local host.  It is referred to by programs that need to translate
    between host names and DARPA Internet addresses when the name server (see
    named(ADMN)) is not being used.  Each line in the file describes a single
    host on the network and consists of three fields separated by any number
    of blanks or tabs:

       address name aliases ...

    where

    address     is the DARPA Internet address.  Unless another type of
                address is required by some host on the network, address
                should be a Class A address, which takes the form net.node
                where net is the network number from /etc/networks (see
                networks(SFF)), which must be between 0 and 127; and node is
                a value which must be unique for each host and be between 0
                and 16777215.

    name        is the official name of the host.  If the host has the same
                operating system as your system, it must claim this host name
                by executing hostname(ADMN) when it is initializing itself.

    aliases     is a list of alternate names for the host.  Aliases can be
                used in network commands in place of the official name.

    It is suggested that you specify the hostname and the node name (see
    hostname(TC) and uname(C)) as aliases of one another for each machine
    listed in the /etc/hosts file.

    The routines which search this file ignore comments (portions of lines
    beginning with ``#'') and blank lines.

    Internet addresses can actually take one of four forms:

    A           A is a simple 32-bit integer.

    A . B       A is an eight-bit quantity occupying the high-order byte and
                B is a 24-bit quantity occupying the remaining bytes.  This
                form is suitable for a Class A address of the form net .
                node.

    A . B . C   A is an eight-bit quantity occupying the high-order byte; B
                is an eight-bit quantity occupying the next byte; and C is a
                16-bit quantity occupying the remaining bytes.  This form is
                suitable for a Class B address of the form 128.net.node.

    A . B . C . D
                The four parts each occupy a byte in the address.


 Files

    /etc/hosts

 Examples


       #       Engineering network
       128.212.64.1    morannon.eng.xyz.com morannon
       128.212.64.2    grinch.eng.xyz.com grinch
       128.212.64.85   ozzy.eng.xyz.com ozzy   # SLC [stevea]


 See also

    hostname(TC), inet(ADMP), networks(SFF), uname(C)