usr/src/share/man/man5/hosts.5

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)hosts.5	8.2 (Berkeley) 12/11/93
.\"
.Dd December 11, 1993
.Dt HOSTS 5
.Os BSD 4.2
.Sh NAME
.Nm hosts
.Nd host name data base
.Sh DESCRIPTION
The
.Nm hosts
file contains information regarding
the known hosts on the network.
For each host a single line should be present
with the following information:
.Bd -unfilled -offset indent
official host name
Internet address
aliases
.Ed
.Pp
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 which search the file.
.Pp
When using the name server
.Xr named 8 ,
this file provides a backup when the name server
is not running.
For the name server, it is suggested that only a few addresses
be included in this file.
These include  address for the local interfaces that
.Xr ifconfig 8
needs at boot time and a few machines on the local network.
.Pp
This file may be created from the official host
data base maintained at the Network Information Control
Center
.Pq Tn NIC ,
though local changes may be required
to bring it up to date regarding unofficial aliases
and/or unknown hosts.  As the data base maintained at
.Tn NIC
is incomplete, use of the name server is recommended for
sites on the
.Tn DARPA
Internet.
.Pp
Network addresses are specified in the conventional
``.'' (dot) notation using the
.Xr inet_addr 3
routine
from the Internet address manipulation library,
.Xr inet 3 .
Host names may contain any printable
character other than a field delimiter, newline,
or comment character.
.Sh FILES
.Bl -tag -width /etc/hosts -compact
.It Pa /etc/hosts
The
.Nm hosts
file resides in
.Pa /etc .
.El
.Sh SEE ALSO
.Xr gethostbyname 3 ,
.Xr ifconfig 8 ,
.Xr named 8
.Rs
.%T "Name Server Operations Guide for BIND"
.Re
.Sh HISTORY
The
.Nm
file format appeared in
.Bx 4.2 .
Commit	Line	Data
	1	.\" Copyright (c) 1983, 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	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. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)hosts.5 8.2 (Berkeley) 12/11/93
	33	.\"
	34	.Dd December 11, 1993
	35	.Dt HOSTS 5
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm hosts
	39	.Nd host name data base
	40	.Sh DESCRIPTION
	41	The
	42	.Nm hosts
	43	file contains information regarding
	44	the known hosts on the network.
	45	For each host a single line should be present
	46	with the following information:
	47	.Bd -unfilled -offset indent
	48	official host name
	49	Internet address
	50	aliases
	51	.Ed
	52	.Pp
	53	Items are separated by any number of blanks and/or
	54	tab characters. A ``#'' indicates the beginning of
	55	a comment; characters up to the end of the line are
	56	not interpreted by routines which search the file.
	57	.Pp
	58	When using the name server
	59	.Xr named 8 ,
	60	this file provides a backup when the name server
	61	is not running.
	62	For the name server, it is suggested that only a few addresses
	63	be included in this file.
	64	These include address for the local interfaces that
	65	.Xr ifconfig 8
	66	needs at boot time and a few machines on the local network.
	67	.Pp
	68	This file may be created from the official host
	69	data base maintained at the Network Information Control
	70	Center
	71	.Pq Tn NIC ,
	72	though local changes may be required
	73	to bring it up to date regarding unofficial aliases
	74	and/or unknown hosts. As the data base maintained at
	75	.Tn NIC
	76	is incomplete, use of the name server is recommended for
	77	sites on the
	78	.Tn DARPA
	79	Internet.
	80	.Pp
	81	Network addresses are specified in the conventional
	82	``.'' (dot) notation using the
	83	.Xr inet_addr 3
	84	routine
	85	from the Internet address manipulation library,
	86	.Xr inet 3 .
	87	Host names may contain any printable
	88	character other than a field delimiter, newline,
	89	or comment character.
	90	.Sh FILES
	91	.Bl -tag -width /etc/hosts -compact
	92	.It Pa /etc/hosts
	93	The
	94	.Nm hosts
	95	file resides in
	96	.Pa /etc .
	97	.El
	98	.Sh SEE ALSO
	99	.Xr gethostbyname 3 ,
	100	.Xr ifconfig 8 ,
	101	.Xr named 8
	102	.Rs
	103	.%T "Name Server Operations Guide for BIND"
	104	.Re
	105	.Sh HISTORY
	106	The
	107	.Nm
	108	file format appeared in
	109	.Bx 4.2 .