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2 .\" Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
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16 .\" $Id: nsupdate.8,v 1.24.2.4 2004/03/15 04:44:41 marka Exp $
18 .TH "NSUPDATE" "8" "Jun 30, 2000" "BIND9" ""
20 nsupdate \- Dynamic DNS update utility
23 \fBnsupdate\fR [ \fB-d\fR ] [ \fB [ -y \fIkeyname:secret\fB ] [ -k \fIkeyfile\fB ] \fR ] [ \fB-v\fR ] [ \fBfilename\fR ]
27 is used to submit Dynamic DNS Update requests as defined in RFC2136
29 This allows resource records to be added or removed from a zone
30 without manually editing the zone file.
31 A single update request can contain requests to add or remove more than one
34 Zones that are under dynamic control via
36 or a DHCP server should not be edited by hand.
38 conflict with dynamic updates and cause data to be lost.
40 The resource records that are dynamically added or removed with
42 have to be in the same zone.
43 Requests are sent to the zone's master server.
44 This is identified by the MNAME field of the zone's SOA record.
50 operate in debug mode.
51 This provides tracing information about the update requests that are
52 made and the replies received from the name server.
54 Transaction signatures can be used to authenticate the Dynamic DNS
56 These use the TSIG resource record type described in RFC2845.
57 The signatures rely on a shared secret that should only be known to
60 Currently, the only supported encryption algorithm for TSIG is
61 HMAC-MD5, which is defined in RFC 2104.
62 Once other algorithms are defined for TSIG, applications will need to
63 ensure they select the appropriate algorithm as well as the key when
64 authenticating each other.
69 statements would be added to
71 so that the name server can associate the appropriate secret key
72 and algorithm with the IP address of the
73 client application that will be using TSIG authentication.
76 \fI/etc/named.conf\fR.
83 option to provide the shared secret needed to generate a TSIG record
84 for authenticating Dynamic DNS update requests.
85 These options are mutually exclusive.
90 reads the shared secret from the file
92 whose name is of the form
93 \fIK{name}.+157.+{random}.private\fR.
96 \fIK{name}.+157.+{random}.key\fR
97 must also be present. When the
99 option is used, a signature is generated from
100 \fIkeyname:secret.\fR
102 is the name of the key,
105 is the base64 encoded shared secret.
108 option is discouraged because the shared secret is supplied as a command
109 line argument in clear text.
110 This may be visible in the output from
112 or in a history file maintained by the user's shell.
116 uses UDP to send update requests to the name server.
121 use a TCP connection.
122 This may be preferable when a batch of update requests is made.
129 Each command is supplied on exactly one line of input.
130 Some commands are for administrative purposes.
131 The others are either update instructions or prerequisite checks on the
132 contents of the zone.
133 These checks set conditions that some name or set of
134 resource records (RRset) either exists or is absent from the zone.
135 These conditions must be met if the entire update request is to succeed.
136 Updates will be rejected if the tests for the prerequisite conditions fail.
138 Every update request consists of zero or more prerequisites
139 and zero or more updates.
140 This allows a suitably authenticated update request to proceed if some
141 specified resource records are present or missing from the zone.
142 A blank input line (or the \fBsend\fR command) causes the
143 accumulated commands to be sent as one Dynamic DNS update request to the
146 The command formats and their meaning are as follows:
148 \fBserver servername [ port ]\fR
149 Sends all dynamic update requests to the name server
151 When no server statement is provided,
153 will send updates to the master server of the correct zone.
154 The MNAME field of that zone's SOA record will identify the master
155 server for that zone.
157 is the port number on
159 where the dynamic update requests get sent.
160 If no port number is specified, the default DNS port number of 53 is
163 \fBlocal address [ port ]\fR
164 Sends all dynamic update requests using the local
166 When no local statement is provided,
168 will send updates using an address and port chosen by the system.
170 can additionally be used to make requests come from a specific port.
171 If no port number is specified, the system will assign one.
174 Specifies that all updates are to be made to the zone
178 statement is provided,
180 will attempt determine the correct zone to update based on the rest of the input.
182 \fBclass classname\fR
183 Specify the default class.
184 If no \fIclass\fR is specified the default class is
187 \fBkey name secret\fR
188 Specifies that all updates are to be TSIG signed using the
189 \fIkeyname\fR \fIkeysecret\fR pair.
190 The \fBkey\fR command
191 overrides any key specified on the command line via
192 \fB-y\fR or \fB-k\fR.
194 \fBprereq nxdomain domain-name\fR
195 Requires that no resource record of any type exists with name
198 \fBprereq yxdomain domain-name\fR
201 exists (has as at least one resource record, of any type).
203 \fBprereq nxrrset domain-name [ class ] type\fR
204 Requires that no resource record exists of the specified
211 is omitted, IN (internet) is assumed.
213 \fBprereq yxrrset domain-name [ class ] type\fR
214 This requires that a resource record of the specified
222 is omitted, IN (internet) is assumed.
224 \fBprereq yxrrset domain-name [ class ] type data\fI...\fB\fR
227 from each set of prerequisites of this form
233 are combined to form a set of RRs. This set of RRs must
234 exactly match the set of RRs existing in the zone at the
242 are written in the standard text representation of the resource record's
245 \fBupdate delete domain-name [ ttl ] [ class ] [ type [ data\fI...\fB ] ]\fR
246 Deletes any resource records named
252 is provided, only matching resource records will be removed.
253 The internet class is assumed if
257 is ignored, and is only allowed for compatibility.
259 \fBupdate add domain-name ttl [ class ] type data\fI...\fB\fR
260 Adds a new resource record with the specified
267 Displays the current message, containing all of the prerequisites and
268 updates specified since the last send.
271 Sends the current message. This is equivalent to entering a blank line.
273 Lines beginning with a semicolon are comments and are ignored.
276 The examples below show how
278 could be used to insert and delete resource records from the
281 Notice that the input in each example contains a trailing blank line so that
282 a group of commands are sent as one dynamic update request to the
283 master name server for
288 > update delete oldhost.example.com A
289 > update add newhost.example.com 86400 A 172.16.1.1
295 \fBoldhost.example.com\fR
298 \fBnewhost.example.com\fR
299 it IP address 172.16.1.1 is added.
300 The newly-added record has a 1 day TTL (86400 seconds)
304 > prereq nxdomain nickname.example.com
305 > update add nickname.example.com 86400 CNAME somehost.example.com
310 The prerequisite condition gets the name server to check that there
311 are no resource records of any type for
312 \fBnickname.example.com\fR.
313 If there are, the update request fails.
314 If this name does not exist, a CNAME for it is added.
315 This ensures that when the CNAME is added, it cannot conflict with the
316 long-standing rule in RFC1034 that a name must not exist as any other
317 record type if it exists as a CNAME.
318 (The rule has been updated for DNSSEC in RFC2535 to allow CNAMEs to have
319 SIG, KEY and NXT records.)
322 \fB/etc/resolv.conf\fR
323 used to identify default name server
325 \fBK{name}.+157.+{random}.key\fR
326 base-64 encoding of HMAC-MD5 key created by
327 \fBdnssec-keygen\fR(8).
329 \fBK{name}.+157.+{random}.private\fR
330 base-64 encoding of HMAC-MD5 key created by
331 \fBdnssec-keygen\fR(8).
341 \fBdnssec-keygen\fR(8).
344 The TSIG key is redundantly stored in two separate files.
345 This is a consequence of nsupdate using the DST library
346 for its cryptographic operations, and may change in future