7204N/A - Copyright (C) 2000, 2001 Internet Software Consortium. 7204N/A - Permission to use, copy, modify, and distribute this software for any 7204N/A - purpose with or without fee is hereby granted, provided that the above 7204N/A - copyright notice and this permission notice appear in all copies. 7204N/A - THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM 7204N/A - DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL 7204N/A - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL 7204N/A - INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, 7300N/A - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING 7204N/A - FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 7204N/A - NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 7204N/A - WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. CONTENT="Modular DocBook HTML Stylesheet Version 1.61 >nsupdate -- Dynamic DNS update utility</
DIVis used to submit Dynamic DNS Update requests as defined in RFC2136
This allows resource records to be added or removed from a zone
without manually editing the zone file.
A single update request can contain requests to add or remove more than one
>Zones that are under dynamic control via
or a DHCP server should not be edited by hand.
conflict with dynamic updates and cause data to be lost.</
P>The resource records that are dynamically added or removed with
have to be in the same zone.
Requests are sent to the zone's master server.
This is identified by the MNAME field of the zone's SOA record.</
PThis provides tracing information about the update requests that are
made and the replies received from the name server.</
P>Transaction signatures can be used to authenticate the Dynamic DNS
These use the TSIG resource record type described in RFC2845.
The signatures rely on a shared secret that should only be known to
Currently, the only supported encryption algorithm for TSIG is
HMAC-MD5, which is defined in RFC 2104.
Once other algorithms are defined for TSIG, applications will need to
ensure they select the appropriate algorithm as well as the key when
authenticating each other.
statements would be added to
so that the name server can associate the appropriate secret key
and algorithm with the IP address of the
client application that will be using TSIG authentication.
option to provide the shared secret needed to generate a TSIG record
for authenticating Dynamic DNS update requests.
These options are mutually exclusive.
reads the shared secret from the file
whose name is of the form
>K{name}.+157.+{random}.private</
TT>K{name}.+157.+{random}.key</
TTmust also be present. When the
option is used, a signature is generated from
is the base64 encoded shared secret.
option is discouraged because the shared secret is supplied as a command
line argument in clear text.
This may be visible in the output from
or in a history file maintained by the user's shell.</
Puses UDP to send update requests to the name server.
This may be preferable when a batch of update requests is made.</
PEach command is supplied on exactly one line of input.
Some commands are for administrative purposes.
The others are either update instructions or prerequisite checks on the
These checks set conditions that some name or set of
resource records (RRset) either exists or is absent from the zone.
These conditions must be met if the entire update request is to succeed.
Updates will be rejected if the tests for the prerequisite conditions fail.</
P>Every update request consists of zero or more prerequisites
and zero or more updates.
This allows a suitably authenticated update request to proceed if some
specified resource records are present or missing from the zone.
A blank input line causes the accumulated commands to be sent as one Dynamic
DNS update request to the name server.</
P>The command formats and their meaning are as follows:
>Sends all dynamic update requests to the name server
When no server statement is provided,
will send updates to the master server of the correct zone.
The MNAME field of that zone's SOA record will identify the master
where the dynamic update requests get sent.
If no port number is specified, the default DNS port number of 53 is
>Sends all dynamic update requests using the local
When no local statement is provided,
will send updates using an address and port choosen by the system.
can additionally be used to make requests come from a specific port.
If no port number is specified, the system will assign one. </
P>Specifies that all updates are to be made to the zone
will attempt determine the correct zone to update based on the rest of the input.</
P>Requires that no resource record of any type exists with name
exists (has as at least one resource record, of any type).</
P> {domain-name} [class] {type}</
P>Requires that no resource record exists of the specified
is omitted, IN (internet) is assumed.
> {domain-name} [class] {type}</
P>This requires that a resource record of the specified
is omitted, IN (internet) is assumed.</
P> {domain-name} [class] {type} {data...}</
Pfrom each set of prerequisites of this form
are combined to form a set of RRs. This set of RRs must
exactly match the set of RRs existing in the zone at the
are written in the standard text representation of the resource record's
> {domain-name} [ttl] [class] [type [data...]]</
P>Deletes any resource records named
is provided, only matching resource records will be removed.
The internet class is assumed if
is ignored, and is only allowed for compatibility.</
P> {domain-name} {ttl} [class] {type} {data...}</
P>Adds a new resource record with the specified
>Lines beginning with a semicolon are comments, and are ignored.</
P>The examples below show how
could be used to insert and delete resource records from the
Notice that the input in each example contains a trailing blank line so that
a group of commands are sent as one dynamic update request to the
it IP address 172.16.1.1 is added.
The newly-added record has a 1 day TTL (86400 seconds)
>The prerequisite condition gets the name server to check that there
are no resource records of any type for
If there are, the update request fails.
If this name does not exist, a CNAME for it is added.
This ensures that when the CNAME is added, it cannot conflict with the
long-standing rule in RFC1034 that a name must not exist as any other
record type if it exists as a CNAME.
(The rule has been updated for DNSSEC in RFC2535 to allow CNAMEs to have
SIG, KEY and NXT records.)</
P>used to identify default name server</
P>K{name}.+157.+{random}.key</
TT>base-64 encoding of HMAC-MD5 key created by
>K{name}.+157.+{random}.private</
TT>base-64 encoding of HMAC-MD5 key created by
>The TSIG key is redundantly stored in two separate files.
This is a consequence of nsupdate using the DST library
for its cryptographic operations, and may change in future