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Manual Reference Pages  -  KNSUPDATE (1)


knsupdate - Dynamic DNS update utility \$1 \n[an-margin] level \n[rst2man-indent-level] level margin: \n[rst2man-indent\n[rst2man-indent-level]] - \n[rst2man-indent0] \n[rst2man-indent1] \n[rst2man-indent2]


See Also


knsupdate [options] [filename]


This utility sends Dynamic DNS update messages to a DNS server. Update content is read from a file (if the parameter filename is given) or from the standard input.

The format of updates is textual and is made up of commands. Every command is placed on the separate line of the input. Lines starting with a semicolon are comments and are not processed.


-d Enable debug messages.
-h, --help Print the program help.
-k keyfile
  Use the TSIG key stored in a file keyfile to authenticate the request. The file should contain the key in the same format, which is accepted by the -y option.
-p port Set the port to use for connections to the server (if not explicitly specified in the update). The default is 53.
-r retries
  The number of retries for UDP requests. The default is 3.
-t timeout
  The total timeout (for all UDP update tries) of the update request in seconds. The default is 12. If set to zero, the timeout is infinite.
-v Use a TCP connection.
-V, --version
  Print the program version.
-y [alg:]name:key
  Use the TSIG key with a name name to authenticate the request. The alg part specifies the algorithm (the default is hmac-md5) and key specifies the shared secret encoded in Base64.


server name [port]
  Specifies a receiving server of the dynamic update message. The name parameter can be either a host name or an IP address. If the port is not specified, the default port is used. The default port value can be controlled using the -p program option.
local address [port]
  Specifies outgoing address and port. If no local is specified, the address and port are set by the system automatically. The default port number is 0.
zone name
  Specifies that all updates are done within a zone name. If not used, the default zone is the root zone.
origin name
  Specifies fully qualified domain name suffix which is appended to non-fqd owners in update commands. The default origin is the root zone.
class name
  Sets name as the default class for all updates. If not used, the default class is IN.
ttl value
  Sets value as the default TTL (in seconds). If not used, the default value is 0.
key [alg:]name key
  Specifies the TSIG key named name to authenticate the request. An optional alg algorithm can be specified. This command has the same effect as the program option -y.
[prereq] nxdomain name
  Adds a prerequisite for a non-existing record owned by name.
[prereq] yxdomain name
  Adds a prerequisite for an existing record owned by name.
[prereq] nxrrset name [class] type
  Adds a prerequisite for a non-existing record of the type owned by name. Internet class is expected.
[prereq] yxrrset name [class] type [data]
  Adds a prerequisite for an existing record of the type owned by name with optional data. Internet class is expected.
[update] add name [ttl] [class] type data
  Adds a request to add a new resource record into the zone. Please note that if the name is not fully qualified domain name, the current origin name is appended to it.
[update] del[ete] name [ttl] [class] [type] [data]
  Adds a request to remove all (or matching class, type or data) resource records from the zone. There is the same requirement for the name parameter as in update add command. The ttl item is ignored.
show Displays current content of the update message.
send Sends the current update message and cleans the list of updates.
answer Displays the last answer from the server.
debug Enable debugging. This command has the same meaning as the -d program option.
quit Quit the program.


Options -k and -y can not be used simultaneously.

Missing features with regard to ISC nsupdate: Authentication using GSS-TSIG or SIG(0).

Options -D, -g, -o, -l, -L, -R and -u.

Commands: gsstsig, oldgsstsig and realm.

Differences with regard to ISC nsupdate: Zone name/server guessing, if the zone name/server is not specified.

Empty line doesn\(aqt send the update.

BIND-like key format (ddns-confgen output) is not supported.


1. Send one update of the zone to the server The update contains two new records:

$ knsupdate
> server
> zone
> origin
> ttl 3600
> add 7200 A
> add test2 TXT "hello"
> show
> send
> answer
> quit


kdig(1), khost(1).


CZ.NIC Labs <>


Copyright 2010–2016, CZ.NIC, z.s.p.o.
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2.1.1 KNSUPDATE (1) 2016-02-10

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