94 lines
4.1 KiB
Groff
94 lines
4.1 KiB
Groff
.\" Copyright (c) 1987, 1990 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.
|
|
.\"
|
|
.\" from: @(#)hostname.7 6.5 (Berkeley) 6/24/90
|
|
.\" $Id: hostname.7,v 1.3 1994/03/24 10:11:48 deraadt Exp $
|
|
.\"
|
|
.Dd June 24, 1990
|
|
.Dt HOSTNAME 7
|
|
.Os BSD 4.2
|
|
.Sh NAME
|
|
.Nm hostname
|
|
.Nd host name resolution description
|
|
.Sh DESCRIPTION
|
|
Hostnames are domains, where a domain is a hierarchical, dot-separated
|
|
list of subdomains; for example, the machine monet, in the Berkeley
|
|
subdomain of the EDU subdomain of the Internet would be represented as
|
|
.Pp
|
|
.Dl monet.Berkeley.EDU
|
|
.Pp
|
|
(with no trailing dot).
|
|
.Pp
|
|
Hostnames are often used with network client and server programs,
|
|
which must generally translate the name to an address for use.
|
|
(This function is generally performed by the library routine
|
|
.Xr gethostbyname 3 . )
|
|
Hostnames are resolved by the Internet name resolver in the following
|
|
fashion.
|
|
.Pp
|
|
If the name consists of a single component, i.e. contains no dot,
|
|
and if the environment variable
|
|
.Dq Ev HOSTALIASES
|
|
is set to the name of a file,
|
|
that file is searched for an string matching the input hostname.
|
|
The file should consist of lines made up of two white-space separated strings,
|
|
the first of which is the hostname alias,
|
|
and the second of which is the complete hostname
|
|
to be substituted for that alias.
|
|
If a case-insensitive match is found between the hostname to be resolved
|
|
and the first field of a line in the file, the substituted name is looked
|
|
up with no further processing.
|
|
.Pp
|
|
If the input name ends with a trailing dot,
|
|
the trailing dot is removed,
|
|
and the remaining name is looked up with no further processing.
|
|
.Pp
|
|
If the input name does not end with a trailing dot, it is looked up
|
|
by searching through a list of domains until a match is found.
|
|
The default search list includes first the local domain,
|
|
then its parent domains with at least 2 name components (longest first).
|
|
For example,
|
|
in the domain CS.Berkeley.EDU, the name lithium.CChem will be checked first
|
|
as lithium.CChem.CS.Berkeley.EDU and then as lithium.CChem.Berkeley.EDU.
|
|
Lithium.CChem.EDU will not be tried, as the there is only one component
|
|
remaining from the local domain.
|
|
The search path can be changed from the default
|
|
by a system-wide configuration file (see
|
|
.Xr resolv.conf 5 ) .
|
|
.Sh SEE ALSO
|
|
.Xr gethostbyname 3 ,
|
|
.Xr resolv.conf 5 ,
|
|
.Xr mailaddr 7 ,
|
|
.Xr named 8
|
|
.Sh HISTORY
|
|
.Nm Hostname
|
|
appeared in 4.2 BSD.
|