1<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" 2 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" 3 [<!ENTITY mdash "—">]> 4<!-- 5 - Copyright (C) 2004-2012 Internet Systems Consortium, Inc. ("ISC") 6 - Copyright (C) 2000-2003 Internet Software Consortium. 7 - 8 - Permission to use, copy, modify, and/or distribute this software for any 9 - purpose with or without fee is hereby granted, provided that the above 10 - copyright notice and this permission notice appear in all copies. 11 - 12 - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 13 - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 14 - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 15 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 16 - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 17 - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 18 - PERFORMANCE OF THIS SOFTWARE. 19--> 20 21<!-- $Id$ --> 22<refentry id="man.nsupdate"> 23 <refentryinfo> 24 <date>Aug 25, 2009</date> 25 </refentryinfo> 26 <refmeta> 27 <refentrytitle><application>nsupdate</application></refentrytitle> 28 <manvolnum>1</manvolnum> 29 <refmiscinfo>BIND9</refmiscinfo> 30 </refmeta> 31 <refnamediv> 32 <refname><application>nsupdate</application></refname> 33 <refpurpose>Dynamic DNS update utility</refpurpose> 34 </refnamediv> 35 36 <docinfo> 37 <copyright> 38 <year>2004</year> 39 <year>2005</year> 40 <year>2006</year> 41 <year>2007</year> 42 <year>2008</year> 43 <year>2009</year> 44 <year>2010</year> 45 <year>2011</year> 46 <year>2012</year> 47 <holder>Internet Systems Consortium, Inc. ("ISC")</holder> 48 </copyright> 49 <copyright> 50 <year>2000</year> 51 <year>2001</year> 52 <year>2002</year> 53 <year>2003</year> 54 <holder>Internet Software Consortium.</holder> 55 </copyright> 56 </docinfo> 57 58 <refsynopsisdiv> 59 <cmdsynopsis> 60 <command>nsupdate</command> 61 <arg><option>-d</option></arg> 62 <arg><option>-D</option></arg> 63 <group> 64 <arg><option>-g</option></arg> 65 <arg><option>-o</option></arg> 66 <arg><option>-l</option></arg> 67 <arg><option>-y <replaceable class="parameter"><optional>hmac:</optional>keyname:secret</replaceable></option></arg> 68 <arg><option>-k <replaceable class="parameter">keyfile</replaceable></option></arg> 69 </group> 70 <arg><option>-t <replaceable class="parameter">timeout</replaceable></option></arg> 71 <arg><option>-u <replaceable class="parameter">udptimeout</replaceable></option></arg> 72 <arg><option>-r <replaceable class="parameter">udpretries</replaceable></option></arg> 73 <arg><option>-R <replaceable class="parameter">randomdev</replaceable></option></arg> 74 <arg><option>-v</option></arg> 75 <arg>filename</arg> 76 </cmdsynopsis> 77 </refsynopsisdiv> 78 79 <refsect1> 80 <title>DESCRIPTION</title> 81 <para><command>nsupdate</command> 82 is used to submit Dynamic DNS Update requests as defined in RFC 2136 83 to a name server. 84 This allows resource records to be added or removed from a zone 85 without manually editing the zone file. 86 A single update request can contain requests to add or remove more than 87 one 88 resource record. 89 </para> 90 <para> 91 Zones that are under dynamic control via 92 <command>nsupdate</command> 93 or a DHCP server should not be edited by hand. 94 Manual edits could 95 conflict with dynamic updates and cause data to be lost. 96 </para> 97 <para> 98 The resource records that are dynamically added or removed with 99 <command>nsupdate</command> 100 have to be in the same zone. 101 Requests are sent to the zone's master server. 102 This is identified by the MNAME field of the zone's SOA record. 103 </para> 104 <para> 105 The 106 <option>-d</option> 107 option makes 108 <command>nsupdate</command> 109 operate in debug mode. 110 This provides tracing information about the update requests that are 111 made and the replies received from the name server. 112 </para> 113 <para> 114 The <option>-D</option> option makes <command>nsupdate</command> 115 report additional debugging information to <option>-d</option>. 116 </para> 117 <para> 118 The <option>-L</option> option with an integer argument of zero or 119 higher sets the logging debug level. If zero, logging is disabled. 120 </para> 121 <para> 122 Transaction signatures can be used to authenticate the Dynamic 123 DNS updates. These use the TSIG resource record type described 124 in RFC 2845 or the SIG(0) record described in RFC 2535 and 125 RFC 2931 or GSS-TSIG as described in RFC 3645. TSIG relies on 126 a shared secret that should only be known to 127 <command>nsupdate</command> and the name server. Currently, 128 the only supported encryption algorithm for TSIG is HMAC-MD5, 129 which is defined in RFC 2104. Once other algorithms are 130 defined for TSIG, applications will need to ensure they select 131 the appropriate algorithm as well as the key when authenticating 132 each other. For instance, suitable <type>key</type> and 133 <type>server</type> statements would be added to 134 <filename>/etc/named.conf</filename> so that the name server 135 can associate the appropriate secret key and algorithm with 136 the IP address of the client application that will be using 137 TSIG authentication. SIG(0) uses public key cryptography. 138 To use a SIG(0) key, the public key must be stored in a KEY 139 record in a zone served by the name server. 140 <command>nsupdate</command> does not read 141 <filename>/etc/named.conf</filename>. 142 </para> 143 <para> 144 GSS-TSIG uses Kerberos credentials. Standard GSS-TSIG mode 145 is switched on with the <option>-g</option> flag. A 146 non-standards-compliant variant of GSS-TSIG used by Windows 147 2000 can be switched on with the <option>-o</option> flag. 148 </para> 149 <para><command>nsupdate</command> 150 uses the <option>-y</option> or <option>-k</option> option 151 to provide the shared secret needed to generate a TSIG record 152 for authenticating Dynamic DNS update requests, default type 153 HMAC-MD5. These options are mutually exclusive. 154 </para> 155 <para> 156 When the <option>-y</option> option is used, a signature is 157 generated from 158 <optional><parameter>hmac:</parameter></optional><parameter>keyname:secret.</parameter> 159 <parameter>keyname</parameter> is the name of the key, and 160 <parameter>secret</parameter> is the base64 encoded shared secret. 161 Use of the <option>-y</option> option is discouraged because the 162 shared secret is supplied as a command line argument in clear text. 163 This may be visible in the output from 164 <citerefentry> 165 <refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum> 166 </citerefentry> 167 or in a history file maintained by the user's shell. 168 </para> 169 <para> 170 With the 171 <option>-k</option> option, <command>nsupdate</command> reads 172 the shared secret from the file <parameter>keyfile</parameter>. 173 Keyfiles may be in two formats: a single file containing 174 a <filename>named.conf</filename>-format <command>key</command> 175 statement, which may be generated automatically by 176 <command>ddns-confgen</command>, or a pair of files whose names are 177 of the format <filename>K{name}.+157.+{random}.key</filename> and 178 <filename>K{name}.+157.+{random}.private</filename>, which can be 179 generated by <command>dnssec-keygen</command>. 180 The <option>-k</option> may also be used to specify a SIG(0) key used 181 to authenticate Dynamic DNS update requests. In this case, the key 182 specified is not an HMAC-MD5 key. 183 </para> 184 <para> 185 <command>nsupdate</command> can be run in a local-host only mode 186 using the <option>-l</option> flag. This sets the server address to 187 localhost (disabling the <command>server</command> so that the server 188 address cannot be overridden). Connections to the local server will 189 use a TSIG key found in <filename>/var/run/named/session.key</filename>, 190 which is automatically generated by <command>named</command> if any 191 local master zone has set <command>update-policy</command> to 192 <command>local</command>. The location of this key file can be 193 overridden with the <option>-k</option> option. 194 </para> 195 <para> 196 By default, <command>nsupdate</command> 197 uses UDP to send update requests to the name server unless they are too 198 large to fit in a UDP request in which case TCP will be used. 199 The 200 <option>-v</option> 201 option makes 202 <command>nsupdate</command> 203 use a TCP connection. 204 This may be preferable when a batch of update requests is made. 205 </para> 206 <para> 207 The <option>-p</option> sets the default port number to use for 208 connections to a name server. The default is 53. 209 </para> 210 <para> 211 The <option>-t</option> option sets the maximum time an update request 212 can 213 take before it is aborted. The default is 300 seconds. Zero can be 214 used 215 to disable the timeout. 216 </para> 217 <para> 218 The <option>-u</option> option sets the UDP retry interval. The default 219 is 220 3 seconds. If zero, the interval will be computed from the timeout 221 interval 222 and number of UDP retries. 223 </para> 224 <para> 225 The <option>-r</option> option sets the number of UDP retries. The 226 default is 227 3. If zero, only one update request will be made. 228 </para> 229 <para> 230 The <option>-R <replaceable 231 class="parameter">randomdev</replaceable></option> option 232 specifies a source of randomness. If the operating system 233 does not provide a <filename>/dev/random</filename> or 234 equivalent device, the default source of randomness is keyboard 235 input. <filename>randomdev</filename> specifies the name of 236 a character device or file containing random data to be used 237 instead of the default. The special value 238 <filename>keyboard</filename> indicates that keyboard input 239 should be used. This option may be specified multiple times. 240 </para> 241 </refsect1> 242 243 <refsect1> 244 <title>INPUT FORMAT</title> 245 <para><command>nsupdate</command> 246 reads input from 247 <parameter>filename</parameter> 248 or standard input. 249 Each command is supplied on exactly one line of input. 250 Some commands are for administrative purposes. 251 The others are either update instructions or prerequisite checks on the 252 contents of the zone. 253 These checks set conditions that some name or set of 254 resource records (RRset) either exists or is absent from the zone. 255 These conditions must be met if the entire update request is to succeed. 256 Updates will be rejected if the tests for the prerequisite conditions 257 fail. 258 </para> 259 <para> 260 Every update request consists of zero or more prerequisites 261 and zero or more updates. 262 This allows a suitably authenticated update request to proceed if some 263 specified resource records are present or missing from the zone. 264 A blank input line (or the <command>send</command> command) 265 causes the 266 accumulated commands to be sent as one Dynamic DNS update request to the 267 name server. 268 </para> 269 <para> 270 The command formats and their meaning are as follows: 271 <variablelist> 272 273 <varlistentry> 274 <term> 275 <command>server</command> 276 <arg choice="req">servername</arg> 277 <arg choice="opt">port</arg> 278 </term> 279 <listitem> 280 <para> 281 Sends all dynamic update requests to the name server 282 <parameter>servername</parameter>. 283 When no server statement is provided, 284 <command>nsupdate</command> 285 will send updates to the master server of the correct zone. 286 The MNAME field of that zone's SOA record will identify the 287 master 288 server for that zone. 289 <parameter>port</parameter> 290 is the port number on 291 <parameter>servername</parameter> 292 where the dynamic update requests get sent. 293 If no port number is specified, the default DNS port number of 294 53 is 295 used. 296 </para> 297 </listitem> 298 </varlistentry> 299 300 <varlistentry> 301 <term> 302 <command>local</command> 303 <arg choice="req">address</arg> 304 <arg choice="opt">port</arg> 305 </term> 306 <listitem> 307 <para> 308 Sends all dynamic update requests using the local 309 <parameter>address</parameter>. 310 311 When no local statement is provided, 312 <command>nsupdate</command> 313 will send updates using an address and port chosen by the 314 system. 315 <parameter>port</parameter> 316 can additionally be used to make requests come from a specific 317 port. 318 If no port number is specified, the system will assign one. 319 </para> 320 </listitem> 321 </varlistentry> 322 323 <varlistentry> 324 <term> 325 <command>zone</command> 326 <arg choice="req">zonename</arg> 327 </term> 328 <listitem> 329 <para> 330 Specifies that all updates are to be made to the zone 331 <parameter>zonename</parameter>. 332 If no 333 <parameter>zone</parameter> 334 statement is provided, 335 <command>nsupdate</command> 336 will attempt determine the correct zone to update based on the 337 rest of the input. 338 </para> 339 </listitem> 340 </varlistentry> 341 342 <varlistentry> 343 <term> 344 <command>class</command> 345 <arg choice="req">classname</arg> 346 </term> 347 <listitem> 348 <para> 349 Specify the default class. 350 If no <parameter>class</parameter> is specified, the 351 default class is 352 <parameter>IN</parameter>. 353 </para> 354 </listitem> 355 </varlistentry> 356 357 <varlistentry> 358 <term> 359 <command>ttl</command> 360 <arg choice="req">seconds</arg> 361 </term> 362 <listitem> 363 <para> 364 Specify the default time to live for records to be added. 365 The value <parameter>none</parameter> will clear the default 366 ttl. 367 </para> 368 </listitem> 369 </varlistentry> 370 371 <varlistentry> 372 <term> 373 <command>key</command> 374 <arg choice="req">name</arg> 375 <arg choice="req">secret</arg> 376 </term> 377 <listitem> 378 <para> 379 Specifies that all updates are to be TSIG-signed using the 380 <parameter>keyname</parameter> <parameter>keysecret</parameter> pair. 381 The <command>key</command> command 382 overrides any key specified on the command line via 383 <option>-y</option> or <option>-k</option>. 384 </para> 385 </listitem> 386 </varlistentry> 387 388 <varlistentry> 389 <term> 390 <command>gsstsig</command> 391 </term> 392 <listitem> 393 <para> 394 Use GSS-TSIG to sign the updated. This is equivalent to 395 specifying <option>-g</option> on the commandline. 396 </para> 397 </listitem> 398 </varlistentry> 399 400 <varlistentry> 401 <term> 402 <command>oldgsstsig</command> 403 </term> 404 <listitem> 405 <para> 406 Use the Windows 2000 version of GSS-TSIG to sign the updated. 407 This is equivalent to specifying <option>-o</option> on the 408 commandline. 409 </para> 410 </listitem> 411 </varlistentry> 412 413 <varlistentry> 414 <term> 415 <command>realm</command> 416 <arg choice="req"><optional>realm_name</optional></arg> 417 </term> 418 <listitem> 419 <para> 420 When using GSS-TSIG use <parameter>realm_name</parameter> rather 421 than the default realm in <filename>krb5.conf</filename>. If no 422 realm is specified the saved realm is cleared. 423 </para> 424 </listitem> 425 </varlistentry> 426 427 <varlistentry> 428 <term> 429 <command><optional>prereq</optional> nxdomain</command> 430 <arg choice="req">domain-name</arg> 431 </term> 432 <listitem> 433 <para> 434 Requires that no resource record of any type exists with name 435 <parameter>domain-name</parameter>. 436 </para> 437 </listitem> 438 </varlistentry> 439 440 441 <varlistentry> 442 <term> 443 <command><optional>prereq</optional> yxdomain</command> 444 <arg choice="req">domain-name</arg> 445 </term> 446 <listitem> 447 <para> 448 Requires that 449 <parameter>domain-name</parameter> 450 exists (has as at least one resource record, of any type). 451 </para> 452 </listitem> 453 </varlistentry> 454 455 <varlistentry> 456 <term> 457 <command><optional>prereq</optional> nxrrset</command> 458 <arg choice="req">domain-name</arg> 459 <arg choice="opt">class</arg> 460 <arg choice="req">type</arg> 461 </term> 462 <listitem> 463 <para> 464 Requires that no resource record exists of the specified 465 <parameter>type</parameter>, 466 <parameter>class</parameter> 467 and 468 <parameter>domain-name</parameter>. 469 If 470 <parameter>class</parameter> 471 is omitted, IN (internet) is assumed. 472 </para> 473 </listitem> 474 </varlistentry> 475 476 477 <varlistentry> 478 <term> 479 <command><optional>prereq</optional> yxrrset</command> 480 <arg choice="req">domain-name</arg> 481 <arg choice="opt">class</arg> 482 <arg choice="req">type</arg> 483 </term> 484 <listitem> 485 <para> 486 This requires that a resource record of the specified 487 <parameter>type</parameter>, 488 <parameter>class</parameter> 489 and 490 <parameter>domain-name</parameter> 491 must exist. 492 If 493 <parameter>class</parameter> 494 is omitted, IN (internet) is assumed. 495 </para> 496 </listitem> 497 </varlistentry> 498 499 <varlistentry> 500 <term> 501 <command><optional>prereq</optional> yxrrset</command> 502 <arg choice="req">domain-name</arg> 503 <arg choice="opt">class</arg> 504 <arg choice="req">type</arg> 505 <arg choice="req" rep="repeat">data</arg> 506 </term> 507 <listitem> 508 <para> 509 The 510 <parameter>data</parameter> 511 from each set of prerequisites of this form 512 sharing a common 513 <parameter>type</parameter>, 514 <parameter>class</parameter>, 515 and 516 <parameter>domain-name</parameter> 517 are combined to form a set of RRs. This set of RRs must 518 exactly match the set of RRs existing in the zone at the 519 given 520 <parameter>type</parameter>, 521 <parameter>class</parameter>, 522 and 523 <parameter>domain-name</parameter>. 524 The 525 <parameter>data</parameter> 526 are written in the standard text representation of the resource 527 record's 528 RDATA. 529 </para> 530 </listitem> 531 </varlistentry> 532 533 <varlistentry> 534 <term> 535 <command><optional>update</optional> del<optional>ete</optional></command> 536 <arg choice="req">domain-name</arg> 537 <arg choice="opt">ttl</arg> 538 <arg choice="opt">class</arg> 539 <arg choice="opt">type <arg choice="opt" rep="repeat">data</arg></arg> 540 </term> 541 <listitem> 542 <para> 543 Deletes any resource records named 544 <parameter>domain-name</parameter>. 545 If 546 <parameter>type</parameter> 547 and 548 <parameter>data</parameter> 549 is provided, only matching resource records will be removed. 550 The internet class is assumed if 551 <parameter>class</parameter> 552 is not supplied. The 553 <parameter>ttl</parameter> 554 is ignored, and is only allowed for compatibility. 555 </para> 556 </listitem> 557 </varlistentry> 558 559 <varlistentry> 560 <term> 561 <command><optional>update</optional> add</command> 562 <arg choice="req">domain-name</arg> 563 <arg choice="req">ttl</arg> 564 <arg choice="opt">class</arg> 565 <arg choice="req">type</arg> 566 <arg choice="req" rep="repeat">data</arg> 567 </term> 568 <listitem> 569 <para> 570 Adds a new resource record with the specified 571 <parameter>ttl</parameter>, 572 <parameter>class</parameter> 573 and 574 <parameter>data</parameter>. 575 </para> 576 </listitem> 577 </varlistentry> 578 579 <varlistentry> 580 <term> 581 <command>show</command> 582 </term> 583 <listitem> 584 <para> 585 Displays the current message, containing all of the 586 prerequisites and 587 updates specified since the last send. 588 </para> 589 </listitem> 590 </varlistentry> 591 592 <varlistentry> 593 <term> 594 <command>send</command> 595 </term> 596 <listitem> 597 <para> 598 Sends the current message. This is equivalent to entering a 599 blank line. 600 </para> 601 </listitem> 602 </varlistentry> 603 604 <varlistentry> 605 <term> 606 <command>answer</command> 607 </term> 608 <listitem> 609 <para> 610 Displays the answer. 611 </para> 612 </listitem> 613 </varlistentry> 614 615 <varlistentry> 616 <term> 617 <command>debug</command> 618 </term> 619 <listitem> 620 <para> 621 Turn on debugging. 622 </para> 623 </listitem> 624 </varlistentry> 625 626 </variablelist> 627 </para> 628 629 <para> 630 Lines beginning with a semicolon are comments and are ignored. 631 </para> 632 633 </refsect1> 634 635 <refsect1> 636 <title>EXAMPLES</title> 637 <para> 638 The examples below show how 639 <command>nsupdate</command> 640 could be used to insert and delete resource records from the 641 <type>example.com</type> 642 zone. 643 Notice that the input in each example contains a trailing blank line so 644 that 645 a group of commands are sent as one dynamic update request to the 646 master name server for 647 <type>example.com</type>. 648 649 <programlisting> 650# nsupdate 651> update delete oldhost.example.com A 652> update add newhost.example.com 86400 A 172.16.1.1 653> send 654</programlisting> 655 </para> 656 <para> 657 Any A records for 658 <type>oldhost.example.com</type> 659 are deleted. 660 And an A record for 661 <type>newhost.example.com</type> 662 with IP address 172.16.1.1 is added. 663 The newly-added record has a 1 day TTL (86400 seconds). 664 <programlisting> 665# nsupdate 666> prereq nxdomain nickname.example.com 667> update add nickname.example.com 86400 CNAME somehost.example.com 668> send 669</programlisting> 670 </para> 671 <para> 672 The prerequisite condition gets the name server to check that there 673 are no resource records of any type for 674 <type>nickname.example.com</type>. 675 676 If there are, the update request fails. 677 If this name does not exist, a CNAME for it is added. 678 This ensures that when the CNAME is added, it cannot conflict with the 679 long-standing rule in RFC 1034 that a name must not exist as any other 680 record type if it exists as a CNAME. 681 (The rule has been updated for DNSSEC in RFC 2535 to allow CNAMEs to have 682 RRSIG, DNSKEY and NSEC records.) 683 </para> 684 </refsect1> 685 686 <refsect1> 687 <title>FILES</title> 688 689 <variablelist> 690 <varlistentry> 691 <term><constant>/etc/resolv.conf</constant></term> 692 <listitem> 693 <para> 694 used to identify default name server 695 </para> 696 </listitem> 697 </varlistentry> 698 699 <varlistentry> 700 <term><constant>/var/run/named/session.key</constant></term> 701 <listitem> 702 <para> 703 sets the default TSIG key for use in local-only mode 704 </para> 705 </listitem> 706 </varlistentry> 707 708 <varlistentry> 709 <term><constant>K{name}.+157.+{random}.key</constant></term> 710 <listitem> 711 <para> 712 base-64 encoding of HMAC-MD5 key created by 713 <citerefentry> 714 <refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum> 715 </citerefentry>. 716 </para> 717 </listitem> 718 </varlistentry> 719 720 <varlistentry> 721 <term><constant>K{name}.+157.+{random}.private</constant></term> 722 <listitem> 723 <para> 724 base-64 encoding of HMAC-MD5 key created by 725 <citerefentry> 726 <refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum> 727 </citerefentry>. 728 </para> 729 </listitem> 730 </varlistentry> 731 732 </variablelist> 733 </refsect1> 734 735 <refsect1> 736 <title>SEE ALSO</title> 737 <para> 738 <citetitle>RFC 2136</citetitle>, 739 <citetitle>RFC 3007</citetitle>, 740 <citetitle>RFC 2104</citetitle>, 741 <citetitle>RFC 2845</citetitle>, 742 <citetitle>RFC 1034</citetitle>, 743 <citetitle>RFC 2535</citetitle>, 744 <citetitle>RFC 2931</citetitle>, 745 <citerefentry> 746 <refentrytitle>named</refentrytitle><manvolnum>8</manvolnum> 747 </citerefentry>, 748 <citerefentry> 749 <refentrytitle>ddns-confgen</refentrytitle><manvolnum>8</manvolnum> 750 </citerefentry>, 751 <citerefentry> 752 <refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum> 753 </citerefentry>. 754 </para> 755 </refsect1> 756 757 <refsect1> 758 <title>BUGS</title> 759 <para> 760 The TSIG key is redundantly stored in two separate files. 761 This is a consequence of nsupdate using the DST library 762 for its cryptographic operations, and may change in future 763 releases. 764 </para> 765 </refsect1> 766</refentry><!-- 767 - Local variables: 768 - mode: sgml 769 - End: 770--> 771