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18 <!-- $Id: nsupdate.html,v 1.9.2.5 2004/03/15 04:44:41 marka Exp $ -->
26 CONTENT=
"Modular DocBook HTML Stylesheet Version 1.73
47 >nsupdate
--
Dynamic DNS update utility
</DIV
49 CLASS=
"REFSYNOPSISDIV"
95 is used to submit Dynamic DNS Update requests as defined in RFC2136
97 This allows resource records to be added or removed from a zone
98 without manually editing the zone file.
99 A single update request can contain requests to add or remove more than one
102 >Zones that are under dynamic control via
107 or a DHCP server should not be edited by hand.
109 conflict with dynamic updates and cause data to be lost.
</P
111 >The resource records that are dynamically added or removed with
116 have to be in the same zone.
117 Requests are sent to the zone's master server.
118 This is identified by the MNAME field of the zone's SOA record.
</P
130 operate in debug mode.
131 This provides tracing information about the update requests that are
132 made and the replies received from the name server.
</P
134 >Transaction signatures can be used to authenticate the Dynamic DNS
136 These use the TSIG resource record type described in RFC2845.
137 The signatures rely on a shared secret that should only be known to
143 Currently, the only supported encryption algorithm for TSIG is
144 HMAC-MD5, which is defined in RFC
2104.
145 Once other algorithms are defined for TSIG, applications will need to
146 ensure they select the appropriate algorithm as well as the key when
147 authenticating each other.
148 For instance suitable
158 statements would be added to
163 so that the name server can associate the appropriate secret key
164 and algorithm with the IP address of the
165 client application that will be using TSIG authentication.
190 option to provide the shared secret needed to generate a TSIG record
191 for authenticating Dynamic DNS update requests.
192 These options are mutually exclusive.
203 reads the shared secret from the file
210 whose name is of the form
213 >K{name}.+
157.+{random}.private
</TT
219 >K{name}.+
157.+{random}.key
</TT
221 must also be present. When the
226 option is used, a signature is generated from
239 is the name of the key,
247 is the base64 encoded shared secret.
253 option is discouraged because the shared secret is supplied as a command
254 line argument in clear text.
255 This may be visible in the output from
259 CLASS=
"REFENTRYTITLE"
263 or in a history file maintained by the user's shell.
</P
270 uses UDP to send update requests to the name server.
281 use a TCP connection.
282 This may be preferable when a batch of update requests is made.
</P
304 Each command is supplied on exactly one line of input.
305 Some commands are for administrative purposes.
306 The others are either update instructions or prerequisite checks on the
307 contents of the zone.
308 These checks set conditions that some name or set of
309 resource records (RRset) either exists or is absent from the zone.
310 These conditions must be met if the entire update request is to succeed.
311 Updates will be rejected if the tests for the prerequisite conditions fail.
</P
313 >Every update request consists of zero or more prerequisites
314 and zero or more updates.
315 This allows a suitably authenticated update request to proceed if some
316 specified resource records are present or missing from the zone.
317 A blank input line (or the
<B
320 > command) causes the
321 accumulated commands to be sent as one Dynamic DNS update request to the
324 >The command formats and their meaning are as follows:
335 > {servername} [port]
</P
339 >Sends all dynamic update requests to the name server
346 When no server statement is provided,
351 will send updates to the master server of the correct zone.
352 The MNAME field of that zone's SOA record will identify the master
353 server for that zone.
360 is the port number on
367 where the dynamic update requests get sent.
368 If no port number is specified, the default DNS port number of
53 is
376 > {address} [port]
</P
380 >Sends all dynamic update requests using the local
388 When no local statement is provided,
393 will send updates using an address and port chosen by the system.
400 can additionally be used to make requests come from a specific port.
401 If no port number is specified, the system will assign one.
</P
412 >Specifies that all updates are to be made to the zone
426 statement is provided,
431 will attempt determine the correct zone to update based on the rest of the input.
</P
442 >Specify the default class.
448 > is specified the default class is
465 >Specifies that all updates are to be TSIG signed using the
481 overrides any key specified on the command line via
499 >Requires that no resource record of any type exists with name
523 exists (has as at least one resource record, of any type).
</P
530 > {domain-name} [class] {type}
</P
534 >Requires that no resource record exists of the specified
561 is omitted, IN (internet) is assumed.
</P
568 > {domain-name} [class] {type}
</P
572 >This requires that a resource record of the specified
600 is omitted, IN (internet) is assumed.
</P
607 > {domain-name} [class] {type} {data...}
</P
618 from each set of prerequisites of this form
639 are combined to form a set of RRs. This set of RRs must
640 exactly match the set of RRs existing in the zone at the
668 are written in the standard text representation of the resource record's
676 > {domain-name} [ttl] [class] [type [data...]]
</P
680 >Deletes any resource records named
701 is provided, only matching resource records will be removed.
702 The internet class is assumed if
716 is ignored, and is only allowed for compatibility.
</P
723 > {domain-name} {ttl} [class] {type} {data...}
</P
727 >Adds a new resource record with the specified
757 >Displays the current message, containing all of the prerequisites and
758 updates specified since the last send.
</P
769 >Sends the current message. This is equivalent to entering a blank line.
</P
775 >Lines beginning with a semicolon are comments and are ignored.
</P
785 >The examples below show how
790 could be used to insert and delete resource records from the
796 Notice that the input in each example contains a trailing blank line so that
797 a group of commands are sent as one dynamic update request to the
798 master name server for
805 CLASS=
"PROGRAMLISTING"
807 > update delete oldhost.example.com A
808 > update add newhost.example.com
86400 A
172.16.1.1
815 >oldhost.example.com
</SPAN
821 >newhost.example.com
</SPAN
823 it IP address
172.16.1.1 is added.
824 The newly-added record has a
1 day TTL (
86400 seconds)
826 CLASS=
"PROGRAMLISTING"
828 > prereq nxdomain nickname.example.com
829 > update add nickname.example.com
86400 CNAME somehost.example.com
833 >The prerequisite condition gets the name server to check that there
834 are no resource records of any type for
837 >nickname.example.com
</SPAN
840 If there are, the update request fails.
841 If this name does not exist, a CNAME for it is added.
842 This ensures that when the CNAME is added, it cannot conflict with the
843 long-standing rule in RFC1034 that a name must not exist as any other
844 record type if it exists as a CNAME.
845 (The rule has been updated for DNSSEC in RFC2535 to allow CNAMEs to have
846 SIG, KEY and NXT records.)
</P
863 >/etc/resolv.conf
</TT
867 >used to identify default name server
</P
872 >K{name}.+
157.+{random}.key
</TT
876 >base-
64 encoding of HMAC-MD5 key created by
880 CLASS=
"REFENTRYTITLE"
888 >K{name}.+
157.+{random}.private
</TT
892 >base-
64 encoding of HMAC-MD5 key created by
896 CLASS=
"REFENTRYTITLE"
915 CLASS=
"REFENTRYTITLE"
922 CLASS=
"REFENTRYTITLE"
929 CLASS=
"REFENTRYTITLE"
936 CLASS=
"REFENTRYTITLE"
943 CLASS=
"REFENTRYTITLE"
950 CLASS=
"REFENTRYTITLE"
957 CLASS=
"REFENTRYTITLE"
964 CLASS=
"REFENTRYTITLE"
977 >The TSIG key is redundantly stored in two separate files.
978 This is a consequence of nsupdate using the DST library
979 for its cryptographic operations, and may change in future