99 lines
3.9 KiB
Groff
99 lines
3.9 KiB
Groff
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.\" Copyright (c) 1986 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms are permitted
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.\" provided that the above copyright notice and this paragraph are
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.\" duplicated in all such forms and that any documentation,
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.\" advertising materials, and other materials related to such
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.\" distribution and use acknowledge that the software was developed
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.\" by the University of California, Berkeley. The name of the
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.\" University may not be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" @(#)resolver.5 5.9 (Berkeley) 12/14/89
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.\"
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.TH RESOLVER 5 "December 14, 1989"
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.UC 4
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.SH NAME
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resolver \- resolver configuration file
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.SH SYNOPSIS
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/etc/resolv.conf
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.SH DESCRIPTION
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.LP
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The
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.I resolver
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is a set of routines in the C library (\c
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.IR resolv (3))
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that provide access to the Internet Domain Name System.
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The resolver configuration file contains information that is read
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by the resolver routines the first time they are invoked by a process.
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The file is designed to be human readable and contains a list of
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keywords with values that provide various types of resolver information.
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.LP
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On a normally configured system this file should not be necessary.
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The only name server to be queried will be on the local machine,
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the domain name is determined from the host name,
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and the domain search path is constructed from the domain name.
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.LP
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The different configuration options are:
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.TP
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\fBnameserver\fP
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Internet address (in dot notation) of a name server
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that the resolver should query.
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Up to MAXNS (currently 3) name servers may be listed,
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one per keyword.
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If there are multiple servers,
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the resolver library queries them in the order listed.
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If no \fBnameserver\fP entries are present,
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the default is to use the name server on the local machine.
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(The algorithm used is to try a name server, and if the query times out,
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try the next, until out of name servers,
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then repeat trying all the name servers
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until a maximum number of retries are made).
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.TP
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\fBdomain\fP
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Local domain name.
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Most queries for names within this domain can use short names
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relative to the local domain.
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If no \fBdomain\fP entry is present, the domain is determined
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from the local host name returned by
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\fIgethostname\fP\|(2);
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the domain part is taken to be everything after the first `.'.
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Finally, if the host name does not contain a domain part, the root
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domain is assumed.
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.TP
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\fBsearch\fP
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Search list for host-name lookup.
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The search list is normally determined from the local domain name;
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by default, it begins with the local domain name, then successive
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parent domains that have at least two components in their names.
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This may be changed by listing the desired domain search path
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following the \fIsearch\fP keyword with spaces or tabs separating
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the names.
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Most resolver queries will be attempted using each component
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of the search path in turn until a match is found.
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Note that this process may be slow and will generate a lot of network
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traffic if the servers for the listed domains are not local,
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and that queries will time out if no server is available
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for one of the domains.
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.IP
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The search list is currently limited to six domains
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with a total of 256 characters.
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.LP
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The \fIdomain\fP and \fIsearch\fP keywords are mutually exclusive.
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If more than one instance of these keywords is present,
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the last instance will override.
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.LP
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The keyword and value must appear on a single line, and the keyword
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(e.g. \fBnameserver\fP) must start the line. The value follows
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the keyword, separated by white space.
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.SH FILES
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.I /etc/resolv.conf
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.SH SEE ALSO
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gethostbyname(3N), resolver(3), hostname(7), named(8)
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.br
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Name Server Operations Guide for BIND
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