nsupdate(1M)						  System Administration Commands					      nsupdate(1M)

NAME

       nsupdate - Dynamic DNS update utility

SYNOPSIS

       nsupdate [-dv] [-y keyname:secret | -k keyfile]	[filename]

DESCRIPTION

       The  nsupdate  utility submits Dynamic DNS Update requests as defined in RFC 2136 to a name server. This utility 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 resource record.

       Zones  that are under dynamic control with nsupdate or a DHCP server should not be edited by hand. Manual edits could conflict with dynamic
       updates and cause data to be lost.

       The resource records that are dynamically added or removed with nsupdate must be in the same zone. Requests are sent to the  zone's  master
       servers identified by the MNAME field of the zone's SOA record.

       Transaction  signatures	can be used to authenticate the Dynamic DNS updates using the TSIG resource record type described in RFC 2845. The
       signatures rely on a shared secret that should only be known to nsupdate and the name server.  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
       that they select the appropriate algorithm as well as the key when authenticating each other. For instance, suitable key and server  state-
       ments  would be added to /etc/named.conf 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. The nsupdate utility does not read /etc/named.conf.

       The nsupdate utility uses the -y or -k option to provide the shared secret needed to generate a TSIG record for authenticating Dynamic  DNS
       update requests. These options are mutually exclusive. See OPTIONS.

OPTIONS

       The following options are supported:

       -d		       Operate	in  debug  mode. This provides tracing information about the update requests that are made and the replies
			       received from the name server.

       -k keyfile	       Read the shared secret from the file keyfile, whose name is of the form K{name}.+157.+{random}.private.	 For  his-
			       torical reasons, the file K{name}.+157.+{random}.key must also be present.

       -v		       Use  a  TCP  connection.  Using	a  TCP	connection could be preferable when a batch of update requests is made. By
			       default, nsupdate uses UDP to send update requests to the name server.

       -y keyname:secret       Generate a  signature from keyname:secret, wherekeyname is the name of the key and secret  is  the  base64  encoded
			       shared secret.

			       Use  of the -y option is discouraged because the shared secret is supplied as a command line argument in clear text
			       and could be visible in the output from ps(1) or in a history file maintained by the user's shell.

INPUT FORMAT

       The nsupdate utility reads input from filename or the standard input. Each 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 contents of the zone. 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.

       Every update request consists of zero or more prerequisites and zero or more updates. This condition allows a suitably authenticated update
       request to proceed if some specified resource records are present or missing from the zone. A blank input line (or the send command) causes
       the accumulated commands to be sent as one Dynamic DNS update request to the name server.

       The command formats and their meaning are as follows:

       server servername [ port ]

	   Send  all  dynamic  update  requests to the name server servername. When no server statement is provided, nsupdate sends updates to the
	   master server of the correct zone. The MNAME field of that zone's SOA record identifies the master server for that zone. The port argu-
	   ment  is the port number on servername where the dynamic update requests get sent. If no port number is specified, the default DNS port
	   number of 53 is used.

       local address [ port ]

	   Send all dynamic update requests using the local address. When no local statement is provided, nsupdate sends updates using an  address
	   and	port  chosen  by  the  system. The port argument can also be used to make requests come from a specific port. If no port number is
	   specified, the system assigns one.

       zone zonename

	   Specify that all updates are to be made to the zone zonename. If no zone statement is provided, nsupdate attempts to determine the cor-
	   rect zone to update based on the rest of the input.

       class classname

	   Specify the default class. If no class is specified the default class is IN.

       key name secret

	   Specify  that  all updates are to be TSIG signed using the name secret pair. The key command overrides any key specified on the command
	   line with -y or -k.

       prereq nxdomain domain-name

	   Require that no resource record of any type exists withthe name domain-name.

       prereq yxdomain domain-name

	   Require that domain-name exists (has as at least one resource record, of any type).

       prereq nxrrset domain-name [ class ]  type

	   Require that no resource record exists of the specified type, class and domain-name. If class is omitted, IN (internet) is assumed.

       prereq yxrrset domain-name [ class ]  type

	   Require that a resource record of the specified type, class and domain-name must exist. If class is omitted, IN (internet) is assumed.

       prereq yxrrset domain-name [ class ]  type data...

	   The data from each set of prerequisites of this form sharing a common type, class, and domain-name 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 given type, class, and domain-name. The data are written
	   in the standard text representation of the resource record's RDATA.

       update delete domain-name [ ttl ]  [ class ]  [ type  [ data... ] ]

	   Delete any resource records named domain-name. If type and data are provided, only matching resource records are removed. The  internet
	   class is assumed if class is not supplied. The ttl is ignored, and is only provided for compatibility.

       update add domain-name ttl [ class ]  type data...

	   Add a new resource record with the specified ttl, class and data.

       show

	   Display the current message, containing all of the prerequisites and updates specified since the last send.

       send

	   Sens the current message. This is equivalent to entering a blank line.

       Lines beginning with a semicolon are comments and are ignored.

EXAMPLES

       Example 1: Insert and delete resource records from the zone.

       The  examples  below show how nsupdate could be used to insert and delete resource records from the example.com zone. 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 master name server
       for example.com.

       # nsupdate
       > update delete oldhost.example.com A
       > update add newhost.example.com 86400 A 172.16.1.1
       > send

       Any A records for oldhost.example.com are deleted. An A record for newhost.example.com with IP address 172.16.1.1 is added. The newly-added
       record has a 1 day TTL (86400 seconds).

       # nsupdate
       > prereq nxdomain nickname.example.com
       > update add nickname.example.com 86400 CNAME somehost.example.com
       > send

       The prerequisite condition gets the name server to check that there are no resource records of any type for nickname.example.com. If  there
       are,  the  update request fails. If this name does not exist, a CNAME for it is added. This action ensures that when the CNAME is added, it
       cannot conflict with the long-standing rule in RFC 1034 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 RFC 2535 to allow CNAMEs to have SIG, KEY, and NXT records.)

FILES

       /etc/resolv.conf 	       used to identify default name server

       K{name}.+157.+{random}.key      base-64 encoding of HMAC-MD5 key created by dnssec-keygen(1M).

       K{name}.+157.+{random}.private  base-64 encoding of HMAC-MD5 key created by dnssec-keygen(1M)

BUGS

       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 could change in future releases.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWbind9 		   |
       |Interface Stability	     |External			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       named(1M), dnssec-keygen(1M), attributes(5)

       RFC 2136, RFC 3007, RFC 2104, RFC 2845, RFC 1034, RFC 2535

NOTES

       Source for BIND9 is available in the SUNWbind9S package.

SunOS 5.10							    15 Dec 2004 						      nsupdate(1M)