xref: /freebsd/share/man/man5/hosts.5 (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
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32.\"     @(#)hosts.5	8.2 (Berkeley) 12/11/93
33.\" $FreeBSD$
34.\"
35.Dd December 11, 1993
36.Dt HOSTS 5
37.Os
38.Sh NAME
39.Nm hosts
40.Nd host name data base
41.Sh DESCRIPTION
42The
43.Nm
44file contains information regarding
45the known hosts on the network.
46It can be used in conjunction with DNS, and the NIS
47maps `hosts.byaddr' and `hosts.byname', as controlled by
48.Xr nsswitch.conf 5 .
49For each host a single line should be present
50with the following information:
51.Bd -unfilled -offset indent
52Internet address
53official host name
54aliases
55.Ed
56.Pp
57Items are separated by any number of blanks and/or
58tab characters.
59A ``#'' indicates the beginning of
60a comment; characters up to the end of the line are
61not interpreted by routines which search the file.
62.Pp
63When using the name server
64.Xr named 8 ,
65this file provides a backup used when the name server
66is not running.
67For the name server, it is suggested that only a few addresses
68be included in this file.
69These include addresses for the local interfaces that
70.Xr ifconfig 8
71needs at boot time and a few machines on the local network.
72.Pp
73This file may be created from the official host
74data base maintained at the Network Information Control
75Center
76.Pq Tn NIC ,
77though local changes may be required
78to bring it up to date regarding unofficial aliases
79and/or unknown hosts.
80As the data base maintained at
81.Tn NIC
82is incomplete, use of the name server is recommended for
83sites on the
84.Tn DARPA
85Internet.
86.Pp
87Network addresses are specified in the conventional
88``.'' (dot) notation using the
89.Xr inet_addr 3
90routine
91from the Internet address manipulation library,
92.Xr inet 3 .
93Host names may contain any printable
94character other than a field delimiter, newline,
95or comment character.
96.Sh FILES
97.Bl -tag -width /etc/hosts -compact
98.It Pa /etc/hosts
99The
100.Nm
101file resides in
102.Pa /etc .
103.El
104.Sh SEE ALSO
105.Xr gethostbyname 3 ,
106.Xr nsswitch.conf 5 ,
107.Xr ifconfig 8 ,
108.Xr named 8
109.Rs
110.%T "Name Server Operations Guide for BIND"
111.Re
112.Sh HISTORY
113The
114.Nm
115file format appeared in
116.Bx 4.2 .
117