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Thomassen 13 deSEC, Secure Systems Engineering 14 25 October 2021 16 DNS Catalog Zones 17 draft-ietf-dnsop-dns-catalog-zones-04 19 Abstract 21 This document describes a method for automatic DNS zone provisioning 22 among DNS primary and secondary nameservers by storing and 23 transferring the catalog of zones to be provisioned as one or more 24 regular DNS zones. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on 28 April 2022. 43 Copyright Notice 45 Copyright (c) 2021 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 50 license-info) in effect on the date of publication of this document. 51 Please review these documents carefully, as they describe your rights 52 and restrictions with respect to this document. Code Components 53 extracted from this document must include Simplified BSD License text 54 as described in Section 4.e of the Trust Legal Provisions and are 55 provided without warranty as described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 3. Description . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 4. Catalog Zone Structure . . . . . . . . . . . . . . . . . . . 4 63 4.1. SOA and NS Records . . . . . . . . . . . . . . . . . . . 4 64 4.2. Catalog Zone Schema Version . . . . . . . . . . . . . . . 5 65 4.3. List of Member Zones . . . . . . . . . . . . . . . . . . 5 66 5. Properties . . . . . . . . . . . . . . . . . . . . . . . . . 6 67 5.1. The Change of Ownership (coo) Property . . . . . . . . . 6 68 5.2. The Group Property . . . . . . . . . . . . . . . . . . . 7 69 5.2.1. Group Property Example . . . . . . . . . . . . . . . 7 70 5.3. The Serial Property . . . . . . . . . . . . . . . . . . . 8 71 5.3.1. The SERIAL Resource Record . . . . . . . . . . . . . 9 72 5.3.2. SERIAL RDATA Wire Format . . . . . . . . . . . . . . 9 73 5.3.3. SERIAL Presentation Format . . . . . . . . . . . . . 9 74 5.3.4. SERIAL RR Usage . . . . . . . . . . . . . . . . . . . 9 75 5.4. Custom properties . . . . . . . . . . . . . . . . . . . . 10 76 6. Nameserver Behavior . . . . . . . . . . . . . . . . . . . . . 10 77 6.1. General Requirements . . . . . . . . . . . . . . . . . . 10 78 6.2. Member zone name clash . . . . . . . . . . . . . . . . . 11 79 6.3. Member zone removal . . . . . . . . . . . . . . . . . . . 11 80 6.4. Member node name change . . . . . . . . . . . . . . . . . 11 81 6.5. Migrating member zones between catalogs . . . . . . . . . 11 82 6.6. Zone associated state reset . . . . . . . . . . . . . . . 12 83 7. Implementation Notes . . . . . . . . . . . . . . . . . . . . 12 84 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 85 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 86 9.1. SERIAL RR type . . . . . . . . . . . . . . . . . . . . . 13 87 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 88 11. Normative References . . . . . . . . . . . . . . . . . . . . 14 89 12. Informative References . . . . . . . . . . . . . . . . . . . 15 90 Appendix A. Implementation Status . . . . . . . . . . . . . . . 15 91 Appendix B. Change History (to be removed before final 92 publication) . . . . . . . . . . . . . . . . . . . . . . 16 93 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 95 1. Introduction 97 The content of a DNS zone is synchronized amongst its primary and 98 secondary nameservers using AXFR and IXFR. However, the list of 99 zones served by the primary (called a catalog in [RFC1035]) is not 100 automatically synchronized with the secondaries. To add or remove a 101 zone, the administrator of a DNS nameserver farm not only has to add 102 or remove the zone from the primary, they must also add/remove the 103 zone from all secondaries, either manually or via an external 104 application. This can be both inconvenient and error-prone; it is 105 also dependent on the nameserver implementation. 107 This document describes a method in which the catalog is represented 108 as a regular DNS zone (called a "catalog zone" here), and transferred 109 using DNS zone transfers. As zones are added to or removed from the 110 catalog zone, these changes are distributed to the secondary 111 nameservers in the normal way. The secondary nameservers then 112 add/remove/modify the zones they serve in accordance with the changes 113 to the catalog zone. Other use-cases of nameserver remote 114 configuration by catalog zones are possible, where the catalog 115 consumer might not be a secondary. 117 2. Terminology 119 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 120 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 121 "OPTIONAL" in this document are to be interpreted as described in BCP 122 14 [RFC2119] [RFC8174] when, and only when, they appear in all 123 capitals, as shown here. 125 Catalog zone A DNS zone containing a DNS catalog, that is, a list of 126 DNS zones and associated properties. 128 Member zone A DNS zone whose configuration is published inside a 129 catalog zone. 131 Member node The DNS name in the Catalog zone representing a Member 132 zone. 134 $CATZ Used in examples as a placeholder to represent the domain name 135 of the catalog zone itself. $OLDCATZ and $NEWCATZ are used to 136 discuss migration a member zone from one catalog zone $OLDCATZ to 137 another catalog zone $NEWCATZ. 139 Catalog producer An entity that generates and is responsible for the 140 contents of the catalog zone. 142 Catalog consumer An entity that extracts information from the 143 catalog zone (such as a DNS server that configures itself 144 according to the catalog zone's contents). 146 3. Description 148 A catalog zone is a DNS zone whose contents are specially crafted. 149 Its records primarily constitute a list of PTR records referencing 150 other DNS zones (so-called "member zones"). The catalog zone may 151 contain other records indicating additional metadata (so-called 152 "properties") associated with these member zones. 154 Catalog consumers SHOULD ignore any RR in the catalog zone which is 155 meaningless or useless to the implementation. 157 Authoritative servers may be preconfigured with multiple catalog 158 zones, each associated with a different set of configurations. 160 Although the contents of a catalog zone are interpreted and acted 161 upon by nameservers, a catalog zone is a regular DNS zone and so must 162 adhere to the standards for such zones. 164 A catalog zone is primarily intended for the management of a farm of 165 authoritative nameservers. The content of catalog zones may not be 166 accessible from any recursive nameserver. 168 4. Catalog Zone Structure 170 4.1. SOA and NS Records 172 As with any other DNS zone, a catalog zone MUST have a syntactically 173 correct SOA record and at least one NS record at its apex. 175 The SOA record's SERIAL, REFRESH, RETRY and EXPIRE fields [RFC1035] 176 are used during zone transfer. A catalog zone's SOA SERIAL field 177 MUST increase when an update is made to the catalog zone's contents 178 as per serial number arithmetic defined in [RFC1982]. Otherwise, 179 catalog consumers might not notice updates to the catalog zone's 180 contents. 182 There is no requirement to be able to query the catalog zone via 183 recursive nameservers. Catalog consumers MUST ignore and MUST NOT 184 assume or require NS records at the apex. However, at least one is 185 still required so that catalog zones are syntactically correct DNS 186 zones. A single NS RR with a NSDNAME field containing the absolute 187 name "invalid." is RECOMMENDED [RFC2606]. 189 4.2. Catalog Zone Schema Version 191 The catalog zone schema version is specified by an integer value 192 embedded in a TXT RR named version.$CATZ. All catalog zones MUST 193 have a TXT RRset named version.$CATZ with at least one RR. Catalog 194 consumers MUST NOT apply catalog zone processing to zones without the 195 expected value in one of the RRs in the version.$CATZ TXT RRset, but 196 they may be transferred as ordinary zones. For this memo, the value 197 of one of the RRs in the version.CATZ TXT RRset MUST be set to "2", 198 i.e. 200 version.$CATZ 0 IN TXT "2" 202 NB: Version 1 was used in a draft version of this memo and reflected 203 the implementation first found in BIND 9.11. 205 4.3. List of Member Zones 207 The list of member zones is specified as a collection of member 208 nodes, represented by domain names under the owner name "zones" where 209 "zones" is a direct child domain of the catalog zone. 211 The names of member zones are represented on the RDATA side (instead 212 of as a part of owner names) of a PTR record, so that all valid 213 domain names may be represented regardless of their length [RFC1035]. 214 This PTR record MUST be the only record in the PTR RRset with the 215 same name. More than one record in the RRset denotes a broken 216 catalog zone which MUST NOT be processed (see Section 6.1). 218 For example, if a catalog zone lists three zones "example.com.", 219 "example.net." and "example.org.", the member node RRs would appear 220 as follows: 222 .zones.$CATZ 0 IN PTR example.com. 223 .zones.$CATZ 0 IN PTR example.net. 224 .zones.$CATZ 0 IN PTR example.org. 226 where is a label that tags each record in the collection. 227 has an unique value in the collection. 229 Member node labels carry no informational meaning beyond labeling 230 member zones. A changed label may indicate that the state for a zone 231 needs to be reset (see Section 6.6). 233 Having the zones uniquely tagged with the label ensures 234 that additional RRs can be added below the member node (see 235 Section 5). 237 The CLASS field of every RR in a catalog zone MUST be IN (1). 239 The TTL field's value is not defined by this memo. Catalog zones are 240 for authoritative nameserver management only and are not intended for 241 general querying via recursive resolvers. 243 5. Properties 245 Each member zone MAY have one or more additional properties, 246 described in this chapter. These properties are completely optional 247 and catalog consumers SHOULD ignore those it does not understand. 248 Properties are represented by RRsets below the corresponding member 249 node. 251 5.1. The Change of Ownership (coo) Property 253 The coo property facilitates controlled migration of a member zone 254 from one catalog to another. 256 A Change Of Ownership is signaled by the coo property in the catalog 257 zone currently "owning" the zone. The name of the new catalog is in 258 the value of a PTR record in the old catalog. For example if member 259 "example.com." will migrate from catalog zone $OLDCATZ to catalog 260 zone $NEWCATZ, this appears in the $OLDCATZ catalog zone as follows: 262 .zones.$OLDCATZ 0 IN PTR example.com. 263 coo..zones.$OLDCATZ 0 IN PTR $NEWCATZ 265 The PTR RRset MUST consist of a single PTR record. More than one 266 record in the RRset denotes a broken catalog zone which MUST NOT be 267 processed (see Section 6.1). 269 When a consumer of catalog zone $OLDCATZ receives an update which 270 adds or changes a coo property for a member zone in $OLDCATZ 271 signalling a new owner $NEWCATZ, it does _not_ migrate the member 272 zone immediately. 274 This is because the catalog consumer may not have the 275 identifier associated with the member zone in $NEWCATZ and because 276 name servers do not index Resource Records by RDATA, it may not know 277 wether or not the member zone is configured in $NEWCATZ at all. It 278 may have to wait for an update of $NEWCATZ adding or changing that 279 member zone. When a consumer of catalog zone $NEWCATZ receives an 280 update of $NEWCATZ which adds or changes a member zone, _and_ that 281 consumer had the member zone associated with $OLDCATZ, _and_ there is 282 a coo property of the member zone in $OLDCATZ pointing to $NEWCATZ, 283 _only then_ it will reconfigure the member zone with the for $NEWCATZ 284 preconfigured settings. 286 Unless the member node label (i.e. ) for the member is the 287 same in $NEWCATZ, all associated state for a just migrated zone MUST 288 be reset (see Section 6.6). Note that the owner of $OLDCATZ allows 289 for the zone associated state to be taken over by the owner of 290 $NEWCATZ by default. To prevent the takeover, the owner of $OLDCATZ 291 has to enforce a zone state reset by changing the member node label 292 (see Section 6.6) before or simultaneous with adding the coo 293 property. (see also Section 8) 295 The old owner may remove the member zone containing the coo property 296 from $OLDCATZ once it has been established that all its consumers 297 have processed the Change of Ownership. 299 5.2. The Group Property 301 With a group property, consumer(s) can be signalled to treat some 302 member zones within the catalog zone differently. 304 The consumer MAY apply different configuration options when 305 processing member zones, based on the value of the group property. 306 The exact handling of configuration referred to by the group property 307 value is left to the consumer's implementation and configuration. 308 The property is defined by a TXT record in the sub-node labelled 309 group. 311 The producer MAY assign a group property to all, some, or none of the 312 member zones within a catalog zone. The producer MUST NOT assign 313 more than one group property to one member zone. 315 The consumer MUST ignore either all or none of the group properties 316 in a catalog zone. 318 The value of the TXT record MUST be at most 255 octets long and MUST 319 NOT contain whitespace characters. The consumer MUST interpret the 320 value case-sensitively. 322 5.2.1. Group Property Example 324 .zones.$CATZ 0 IN PTR example.com. 325 group..zones.$CATZ 0 IN TXT sign-with-nsec3 326 .zones.$CATZ 0 IN PTR example.net. 327 group..zones.$CATZ 0 IN TXT nodnssec 329 In this case, the consumer might be implemented and configured in the 330 way that the member zones with "nodnssec" group assigned will not be 331 signed with DNSSEC, and the zones with "sign-with-nsec3" group 332 assigned will be signed with DNSSEC with NSEC3 chain. 334 By generating the catalog zone (snippet) above, the producer signals 335 how the consumer shall treat DNSSEC for the zones example.net. and 336 example.com., respectively. 338 5.3. The Serial Property 340 The serial property helps in increasing reliability of zone update 341 signaling and may help in reducing NOTIFY and SOA query traffic. 343 The current default mechanism for prompting notifications of zone 344 changes from a primary nameserver to the secondaries via DNS NOTIFY 345 [RFC1996], can be unreliable due to packet loss, or secondary 346 nameservers temporarily not being reachable. In such cases the 347 secondary might pick up the change only after the refresh timer runs 348 out, which might take long and be out of the control of the primary 349 nameserver operator. Low refresh values in the zones being served 350 can alleviate update delays, but burden both the primary and 351 secondary nameservers with more refresh queries, especially with 352 larger numbers of secondary nameservers serving large numbers of 353 zones. To mitigate this, updates of zones MAY be signalled via 354 catalog zones with the help of a serial property. 356 The serial number in the SOA record of the most recent version of a 357 member zone MAY be provided by a serial property. When a serial 358 property is present for a member zone, catalog consumers MAY assume 359 this number to be the current serial number in the SOA record of the 360 most recent version of the member zone. 362 Catalog consumers which are secondary for that member zone, MAY 363 compare the serial property with the SOA serial since the last time 364 the zone was fetched. When the serial property is larger, the 365 secondary MAY initiate a zone transfer immediately without doing a 366 SOA query first. The SOA query may be omitted, because the SOA 367 serial has been obtained reliably via the catalog zone already. 369 Secondary nameservers MAY be configured to postpone the next refresh 370 by the SOA refresh value of the member zone (counted since the 371 transfer of the catalog zone) when the value of the serial property 372 was found to be equal to the served zone, the same way as if it had 373 queried the primary SOA directly and found it equal. Note that for 374 this mechanism it is essential that the catalog producer is keeping 375 the serial property up to date with the SOA serial value of the 376 member zone at all times. The catalog may not be lagging behind. 377 Increased robustness in having the latest version of a zone may be a 378 reason to *not* configure a secondary nameserver with this mechanism. 380 Primary nameservers MAY be configured to omit sending DNS NOTIFY 381 messages to secondary nameservers which are known to process the 382 serial property of the member zones in the associated catalog. 383 However they MAY also combine signalling of zone changes with the 384 serial property of a member zone, as well as sending DNS NOTIFY 385 messages, to anticipate slow updates of the catalog zone (due to 386 packet loss or other reasons) and to cater for secondaries that are 387 not a catalog consumer processing the serial property. 389 All comparisons of serial numbers MUST use "Serial number 390 arithmetic", as defined in [RFC1982] 392 5.3.1. The SERIAL Resource Record 394 The serial property value is provided with a SERIAL Resource Record. 395 The Type value for the SERIAL RR is TBD. The SERIAL RR is class 396 independent. The RDATA of the resource record consist of a single 397 field: Serial. 399 5.3.2. SERIAL RDATA Wire Format 401 The SERIAL RDATA wire format is encoded as follows: 403 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 404 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 | Serial | 407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 409 5.3.2.1. The Serial Field 411 The Serial field is a 32-bit unsigned integer in network byte order. 412 It is the serial number of the member zone's SOA record ([RFC1035] 413 section 3.3.13). 415 5.3.3. SERIAL Presentation Format 417 The presentation format of the RDATA portion is as follows: 419 The Serial fields is represented as an unsigned decimal integer. 421 5.3.4. SERIAL RR Usage 423 The serial property of a member zone is provided by a SERIAL RRset 424 with a single SERIAL RR named serial..zones.$CATZ. 426 For example, if a catalog zone lists three zones "example.com.", 427 "example.net." and "example.org.", and a serial property is provided 428 for each of them, the RRs would appear as follows: 430 .zones.$CATZ 0 IN PTR example.com. 431 serial..zones.$CATZ 0 IN SERIAL 3 432 .zones.$CATZ 0 IN PTR example.net. 433 serial..zones.$CATZ 0 IN SERIAL 1634730530 434 .zones.$CATZ 0 IN PTR example.org. 435 serial..zones.$CATZ 0 IN SERIAL 2020112405 437 5.4. Custom properties 439 More properties may be defined in future documents. These future 440 properties will be represented by RRsets directly below the name of a 441 member node. 443 Implementations and operators of catalog zones may choose to provide 444 their own properties. To prevent a name clash with future 445 properties, private properties should be represented below the label 446 ext..zones.$CATZ. ext is not a placeholder, so a custom 447 property would have the domain name .ext..zones.$CATZ 450 6. Nameserver Behavior 452 6.1. General Requirements 454 As it is a regular DNS zone, a catalog zone can be transferred using 455 DNS zone transfers among nameservers. 457 Although they are regular DNS zones, catalog zones contain only 458 information for the management of a set of authoritative nameservers. 459 For this reason, operators may want to limit the systems able to 460 query these zones. It may be inconvenient to serve some contents of 461 catalog zones via DNS queries anyway due to the nature of their 462 representation. A separate method of querying entries inside the 463 catalog zone may be made available by nameserver implementations (see 464 Section 7). 466 Catalog updates should be automatic, i.e., when a nameserver that 467 supports catalog zones completes a zone transfer for a catalog zone, 468 it SHOULD apply changes to the catalog within the running nameserver 469 automatically without any manual intervention. 471 As with regular zones, primary and secondary nameservers for a 472 catalog zone may be operated by different administrators. The 473 secondary nameservers may be configured as catalog consumer to 474 synchronize catalog zones from the primary, but the primary's 475 administrators may not have any administrative access to the 476 secondaries. 478 Nameservers MAY allow loading and transfer of broken zones with 479 incorrect catalog zone syntax (as they are treated as regular zones), 480 but catalog consumers MUST NOT process such broken zones as catalog 481 zones. For the purpose of catalog processing, the broken catalogs 482 MUST be ignored. 484 6.2. Member zone name clash 486 If there is a clash between an existing zone's name (either from an 487 existing member zone or otherwise configured zone) and an incoming 488 member zone's name (via transfer or update), the new instance of the 489 zone MUST be ignored and an error SHOULD be logged. 491 A clash between an existing member zone's name and an incoming member 492 zone's name (via transfer or update), may be an attempt to migrate a 493 zone to a different catalog, but should not be treated as one except 494 as described in {#cooproperty}. 496 6.3. Member zone removal 498 When a member zone is removed from a specific catalog zone, an 499 authoritative server MUST NOT remove the zone and associated state 500 data if the zone was not configured from that specific catalog zone. 501 Only when the zone was configured from a specific catalog zone, and 502 the zone is removed as a member from that specific catalog zone, the 503 zone and associated state (such as zone data and DNSSEC keys) MUST be 504 removed. 506 6.4. Member node name change 508 When via a single update or transfer, the member node's label value 509 () changes, catalog consumers MUST process this as a member 510 zone removal including all the zone's associated state (as described 511 in Section 6.3), immediately followed by processing the member as a 512 newly to be configured zone in the same catalog. 514 6.5. Migrating member zones between catalogs 516 If all consumers of the catalog zones involved support the coo 517 property, it is RECOMMENDED to perform migration of a member zone by 518 following the procedure described in Section 5.1. Otherwise a 519 migration of member zone from a catalog zone $OLDCATZ to a catalog 520 zone $NEWCATZ has to be done by: first removing the member zone from 521 $OLDCATZ; second adding the member zone to $NEWCATZ. 523 If in the process of a migration some consumers of the involved 524 catalog zones did not catch the removal of the member zone from 525 $OLDCATZ yet (because of a lost packet or down time or otherwise), 526 but did already see the update of $NEWCATZ, they may consider the 527 update adding the member zone in $NEWCATZ to be a name clash (see 528 Section 6.2) and as a consequence the member is not migrated to 529 $NEWCATZ. This possibility needs to be anticipated with a member 530 zone migration. Recovery from such a situation is out of the scope 531 of this document. It may for example entail a manually forced 532 retransfer of $NEWCATZ to consumers after they have been detected to 533 have received and processed the removal of the member zone from 534 $OLDCATZ. 536 6.6. Zone associated state reset 538 It may be desirable to reset state (such as zone data and DNSSEC 539 keys) associated with a member zone. 541 A zone state reset may be performed by a change of the member node's 542 name (see Section 6.4). 544 7. Implementation Notes 546 Catalog zones on secondary nameservers would have to be setup 547 manually, perhaps as static configuration, similar to how ordinary 548 DNS zones are configured. The secondary additionally needs to be 549 configured as a catalog consumer for the catalog zone to enable 550 processing of the member zones in the catalog, such as automatic 551 synchronized of the member zones for secondary service. 553 An administrator may want to look at data inside a catalog zone. 554 Typical queries might include dumping the list of member zones, 555 dumping a member zone's effective configuration, querying a specific 556 property value of a member zone, etc. Because of the structure of 557 catalog zones, it may not be possible to perform these queries 558 intuitively, or in some cases, at all, using DNS QUERY. For example, 559 it is not possible to enumerate the contents of a multi-valued 560 property (such as the list of member zones) with a single QUERY. 561 Implementations are therefore advised to provide a tool that uses 562 either the output of AXFR or an out-of-band method to perform queries 563 on catalog zones. 565 8. Security Considerations 567 As catalog zones are transmitted using DNS zone transfers, it is 568 RECOMMENDED that catalog zone transfer are protected from unexpected 569 modifications by way of authentication, for example by using TSIG 570 [RFC8945], or Strict or Mutual TLS authentication with DNS Zone 571 transfer over TLS [RFC9103]. 573 Use of DNS UPDATE [RFC2136] to modify the content of catalog zones 574 SHOULD similarly be authenticated. 576 Zone transfers of member zones SHOULD similarly be authenticated. 577 TSIG shared secrets used for member zones SHOULD NOT be mentioned in 578 the catalog zone data. However, key identifiers may be shared within 579 catalog zones. 581 Catalog zones reveal the zones served by the consumers of the catalog 582 zone. It is RECOMMENDED to limit the systems able to query these 583 zones. It is RECOMMENDED to transfer catalog zones confidentially 584 [RFC9103]. 586 Administrative control over what zones are served from the configured 587 name servers shifts completely from the server operator (consumer) to 588 the "owner" (producer) of the catalog zone content. 590 With migration of member zones between catalogs using the coo 591 property, it is possible for the owner of the target catalog (i.e. 592 $NEWCATZ) to take over all associated state with the zone from the 593 original owner (i.e. $OLDCATZ) by maintaining the same member node 594 label (i.e. ). To prevent the takeover of the zone 595 associated state, the original owner has to enforce a zone state 596 reset by changing the member node label (see Section 6.6) before or 597 simultaneously with adding the coo property. 599 9. IANA Considerations 601 9.1. SERIAL RR type 603 This document defines a new DNS RR type, SERIAL, in the "Resource 604 Record (RR) TYPEs" subregistry of the "Domain Name System (DNS) 605 Parameters" registry: 607 +========+=======+===========================+===========+ 608 | TYPE | Value | Meaning | Reference | 609 +========+=======+===========================+===========+ 610 | SERIAL | TBD | Version number of the | [this | 611 | | | original copy of the zone | document] | 612 +--------+-------+---------------------------+-----------+ 614 Table 1 616 10. Acknowledgements 618 Our deepest thanks and appreciation go to Stephen Morris, Ray Bellis 619 and Witold Krecicki who initiated this draft and did the bulk of the 620 work. 622 Catalog zones originated as the chosen method among various proposals 623 that were evaluated at ISC for easy zone management. The chosen 624 method of storing the catalog as a regular DNS zone was proposed by 625 Stephen Morris. 627 The initial authors discovered that Paul Vixie's earlier [Metazones] 628 proposal implemented a similar approach and reviewed it. Catalog 629 zones borrows some syntax ideas from Metazones, as both share this 630 scheme of representing the catalog as a regular DNS zone. 632 Thanks to Brian Conry, Tony Finch, Evan Hunt, Patrik Lundin, Victoria 633 Risk, Carsten Strotmann, and Kees Monshouwer for reviewing draft 634 proposals and offering comments and suggestions. 636 Thanks to Klaus Darilion who came up with the idea for the serial 637 property during the hackathon at the IETF-109. Thanks also to Shane 638 Kerr, Petr Spacek, Brian Dickson for further brainstorming and 639 discussing the serial property and how it would work best with 640 catalog zones. 642 11. Normative References 644 [RFC1035] Mockapetris, P., "Domain names - implementation and 645 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 646 November 1987, . 648 [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982, 649 DOI 10.17487/RFC1982, August 1996, 650 . 652 [RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone 653 Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996, 654 August 1996, . 656 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 657 Requirement Levels", BCP 14, RFC 2119, 658 DOI 10.17487/RFC2119, March 1997, 659 . 661 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 662 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 663 RFC 2136, DOI 10.17487/RFC2136, April 1997, 664 . 666 [RFC2606] Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS 667 Names", BCP 32, RFC 2606, DOI 10.17487/RFC2606, June 1999, 668 . 670 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 671 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 672 May 2017, . 674 [RFC8945] Dupont, F., Morris, S., Vixie, P., Eastlake 3rd, D., 675 Gudmundsson, O., and B. Wellington, "Secret Key 676 Transaction Authentication for DNS (TSIG)", STD 93, 677 RFC 8945, DOI 10.17487/RFC8945, November 2020, 678 . 680 [RFC9103] Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A. 681 Mankin, "DNS Zone Transfer over TLS", RFC 9103, 682 DOI 10.17487/RFC9103, August 2021, 683 . 685 12. Informative References 687 [Metazones] 688 Vixie, P., "Federated Domain Name Service Using DNS 689 Metazones", 2005, 690 . 692 Appendix A. Implementation Status 694 *Note to the RFC Editor*: please remove this entire section before 695 publication. 697 In the following implementation status descriptions, "DNS Catalog 698 Zones" refers to DNS Catalog Zones as described in this document. 700 * Knot DNS 3.1 (released August 2, 2021) supports full producing and 701 consuming of catalog zones, including the group property. 703 * PowerDNS has a proof of concept external program called PowerCATZ 704 (https://github.com/PowerDNS/powercatz/), that can process DNS 705 Catalog Zones. 707 * Proof of concept python scripts (https://github.com/IETF- 708 Hackathon/NSDCatZ) that can be used for both generating and 709 consuming DNS Catalog Zones with NSD have been developed during 710 the hackathon at the IETF-109. 712 Interoperability between the above implementations has been tested 713 during the hackathon at the IETF-109. 715 Appendix B. Change History (to be removed before final publication) 717 * draft-muks-dnsop-dns-catalog-zones-00 719 | Initial public draft. 721 * draft-muks-dnsop-dns-catalog-zones-01 723 | Added Witold, Ray as authors. Fixed typos, consistency issues. 724 | Fixed references. Updated Area. Removed newly introduced custom 725 | RR TYPEs. Changed schema version to 1. Changed TSIG requirement 726 | from MUST to SHOULD. Removed restrictive language about use of 727 | DNS QUERY. When zones are introduced into a catalog zone, a 728 | primary SHOULD first make the new zones available for transfers 729 | first (instead of MUST). Updated examples, esp. use IPv6 in 730 | examples per Fred Baker. Add catalog zone example. 732 * draft-muks-dnsop-dns-catalog-zones-02 734 | Addressed some review comments by Patrik Lundin. 736 * draft-muks-dnsop-dns-catalog-zones-03 738 | Revision bump. 740 * draft-muks-dnsop-dns-catalog-zones-04 742 | Reordering of sections into more logical order. Separation of 743 | multi-valued properties into their own category. 745 * draft-toorop-dnsop-dns-catalog-zones-00 747 | New authors to pickup the editor pen on this draft 748 | 749 | Remove data type definitions for zone properties Removing 750 | configuration of member zones through zone properties altogether 751 | 752 | Remove Open issues and discussion Appendix, which was about zone 753 | options (including primary/secondary relationships) only. 755 * draft-toorop-dnsop-dns-catalog-zones-01 757 | Added a new section "The Serial Property", introducing a new 758 | mechanism which can help with disseminating zones from the primary 759 | to the secondary nameservers in a timely fashion more reliably. 760 | 761 | Three different ways to provide a "serial" property with a member 762 | zone are offered to or the workgroup for discussion. 763 | 764 | Added a new section "Implementation Status", listing production 765 | ready, upcoming and Proof of Concept implementations, and 766 | reporting on interoperability of the different implementations. 768 * draft-toorop-dnsop-dns-catalog-zones-02 770 | Adding the coo property for zone migration in a controlled fashion 771 | 772 | Adding the group property for reconfigure settings of member zones 773 | in an atomic update 774 | 775 | Adding the epoch property to reset zone associated state in a 776 | controlled fashion 778 * draft-toorop-dnsop-dns-catalog-zones-03 780 | Big cleanup! 781 | 782 | Introducing the terms catalog consumer and catalog producer 783 | 784 | Reorganized topics to create a more coherent whole 785 | 786 | Properties all have consistent format now 787 | 788 | Try to assume the least possible from implementations w.r.t.: 789 | 790 | 1) Predictability of the IDs of member zones 791 | 792 | 2) Whether or not fallback catalog zones can be found for a member 793 | 794 | 3) Whether or not a catalog consumer can maintain state 796 * draft-toorop-dnsop-dns-catalog-zones-04 798 | Move Implementation status to appendix 799 | 800 | Miscellaneous textual improvements 801 | 802 | coo property points to $NEWCATZ (and not zones.$NEWCATZ) 803 | 804 | Remove suggestion to increase serial and remove member zone from 805 | $OLDCATZ after migration 806 | 807 | More consistent usage of the terms catalog consumer and catalog 808 | producer throughout the document 809 | 810 | Better (safer) description of resetting refresh timers of member 811 | zones with the serial property 812 | 813 | Removing a member MUST remove zone associated state 814 | 815 | Make authentication requirements a bit less prescriptive in 816 | security considerations 817 | 818 | Updated implementation status for KnotDNS 819 | 820 | Describe member node name changes and update "Zone associated 821 | state reset" to use that as the mechanism for it. 822 | 823 | Add Peter Thomassen as co-author 824 | 825 | Complete removal of the epoch property. We consider consumer 826 | optimizations with predictable member node labels (for example 827 | based on a hash) out of the scope of this document. 828 | 829 | Miscellaneous editorial improvements 831 Authors' Addresses 833 Peter van Dijk 834 PowerDNS 835 Den Haag 836 Netherlands 838 Email: peter.van.dijk@powerdns.com 840 Libor Peltan 841 CZ.NIC 842 Czechia 844 Email: libor.peltan@nic.cz 845 Ondrej Sury 846 Internet Systems Consortium 847 Czechia 849 Email: ondrej@isc.org 851 Willem Toorop 852 NLnet Labs 853 Science Park 400 854 1098 XH Amsterdam 855 Netherlands 857 Email: willem@nlnetlabs.nl 859 Leo Vandewoestijne 860 Netherlands 862 Email: leo@dns.company 864 Peter Thomassen 865 deSEC, Secure Systems Engineering 866 Berlin 867 Germany 869 Email: peter@desec.io