1 .\" Copyright (c) 1983, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 3. Neither the name of the University nor the names of its contributors
13 .\" may be used to endorse or promote products derived from this software
14 .\" without specific prior written permission.
16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 .\" @(#)hosts.5 8.2 (Berkeley) 12/11/93
36 .Nd host name data base
40 file contains information regarding
41 the known hosts on the network.
42 It can be used in conjunction with DNS, and the NIS
43 maps `hosts.byaddr' and `hosts.byname', as controlled by
45 For each host a single line should be present
46 with the following information:
47 .Bd -unfilled -offset indent
53 Items are separated by any number of blanks and/or
55 A ``#'' indicates the beginning of
56 a comment; characters up to the end of the line are
57 not interpreted by routines which search the file.
59 This file provides a backup used when the name server
61 For the name server, it is suggested that only a few addresses
62 be included in this file.
63 These include addresses for the local interfaces that
65 needs at boot time and a few machines on the local network.
67 This file may be created from the official host
68 data base maintained at the Network Information Control
71 though local changes may be required
72 to bring it up to date regarding unofficial aliases
74 As the data base maintained at
76 is incomplete, use of the name server is recommended for
81 Network addresses are specified in the conventional
82 ``.'' (dot) notation using the
85 from the Internet address manipulation library,
87 Host names may contain any printable
88 character other than a field delimiter, newline,
91 .Bl -tag -width /etc/hosts -compact
100 .Xr nsswitch.conf 5 ,
103 .%T "Name Server Operations Guide for BIND"
108 file format appeared in