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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force D. Wessels 3 Internet-Draft P. Barber 4 Intended status: Standards Track M. Weinberg 5 Expires: June 5, 2020 Verisign 6 W. Kumari 7 Google 8 W. Hardaker 9 USC/ISI 10 December 3, 2019 12 Message Digest for DNS Zones 13 draft-ietf-dnsop-dns-zone-digest-03 15 Abstract 17 This document describes a protocol and new DNS Resource Record that 18 can be used to provide a cryptographic message digest over DNS zone 19 data. The ZONEMD Resource Record conveys the digest data in the zone 20 itself. When a zone publisher includes an ZONEMD record, recipients 21 can verify the zone contents for accuracy and completeness. This 22 provides assurance that received zone data matches published data, 23 regardless of how the zone data has been transmitted and received. 25 ZONEMD is not designed to replace DNSSEC. Whereas DNSSEC protects 26 individual RRSets (DNS data with fine granularity), ZONEMD protects 27 protects a zone's data as a whole, whether consumed by authoritative 28 name servers, recursive name servers, or any other applications. 30 As specified at this time, ZONEMD is not designed for use in large, 31 dynamic zones due to the time and resources required for digest 32 calculation. The ZONEMD record described in this document includes a 33 field intended to enable future work to support large, dynamic zones. 35 Status of This Memo 37 This Internet-Draft is submitted in full conformance with the 38 provisions of BCP 78 and BCP 79. 40 Internet-Drafts are working documents of the Internet Engineering 41 Task Force (IETF). Note that other groups may also distribute 42 working documents as Internet-Drafts. The list of current Internet- 43 Drafts is at https://datatracker.ietf.org/drafts/current/. 45 Internet-Drafts are draft documents valid for a maximum of six months 46 and may be updated, replaced, or obsoleted by other documents at any 47 time. It is inappropriate to use Internet-Drafts as reference 48 material or to cite them other than as "work in progress." 49 This Internet-Draft will expire on June 5, 2020. 51 Copyright Notice 53 Copyright (c) 2019 IETF Trust and the persons identified as the 54 document authors. All rights reserved. 56 This document is subject to BCP 78 and the IETF Trust's Legal 57 Provisions Relating to IETF Documents 58 (https://trustee.ietf.org/license-info) in effect on the date of 59 publication of this document. Please review these documents 60 carefully, as they describe your rights and restrictions with respect 61 to this document. Code Components extracted from this document must 62 include Simplified BSD License text as described in Section 4.e of 63 the Trust Legal Provisions and are provided without warranty as 64 described in the Simplified BSD License. 66 Table of Contents 68 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 69 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4 70 1.2. Design Overview . . . . . . . . . . . . . . . . . . . . . 5 71 1.3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 6 72 1.3.1. Root Zone . . . . . . . . . . . . . . . . . . . . . . 6 73 1.3.2. Providers, Secondaries, and Anycast . . . . . . . . . 6 74 1.3.3. Response Policy Zones . . . . . . . . . . . . . . . . 6 75 1.3.4. Centralized Zone Data Service . . . . . . . . . . . . 7 76 1.3.5. General Purpose Comparison Check . . . . . . . . . . 7 77 1.4. Requirements Language . . . . . . . . . . . . . . . . . . 7 78 2. The ZONEMD Resource Record . . . . . . . . . . . . . . . . . 7 79 2.1. ZONEMD RDATA Wire Format . . . . . . . . . . . . . . . . 8 80 2.1.1. The Serial Field . . . . . . . . . . . . . . . . . . 8 81 2.1.2. The Digest Type Field . . . . . . . . . . . . . . . . 8 82 2.1.3. The Parameter Field . . . . . . . . . . . . . . . . . 8 83 2.1.4. The Digest Field . . . . . . . . . . . . . . . . . . 9 84 2.2. ZONEMD Presentation Format . . . . . . . . . . . . . . . 9 85 2.3. ZONEMD Example . . . . . . . . . . . . . . . . . . . . . 9 86 3. Calculating the Digest . . . . . . . . . . . . . . . . . . . 9 87 3.1. Canonical Format and Ordering . . . . . . . . . . . . . . 9 88 3.1.1. Order of RRSets Having the Same Owner Name . . . . . 10 89 3.1.2. Duplicate RRs . . . . . . . . . . . . . . . . . . . . 10 90 3.2. Add ZONEMD Placeholder . . . . . . . . . . . . . . . . . 10 91 3.3. Optionally Sign the Zone . . . . . . . . . . . . . . . . 10 92 3.4. Calculate the Digest . . . . . . . . . . . . . . . . . . 11 93 3.4.1. SHA384-SIMPLE Calculation . . . . . . . . . . . . . . 11 94 3.4.2. Inclusion/Exclusion Rules . . . . . . . . . . . . . . 11 95 3.5. Update ZONEMD RR . . . . . . . . . . . . . . . . . . . . 12 96 4. Verifying Zone Digest . . . . . . . . . . . . . . . . . . . . 12 97 4.1. Verifying Multiple Digests . . . . . . . . . . . . . . . 13 98 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 99 5.1. ZONEMD RRtype . . . . . . . . . . . . . . . . . . . . . . 13 100 5.2. ZONEMD Digest Type . . . . . . . . . . . . . . . . . . . 14 101 6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 102 6.1. Attacks Against the Zone Digest . . . . . . . . . . . . . 14 103 6.2. Attacks Utilizing the Zone Digest . . . . . . . . . . . . 14 104 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 15 105 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 106 9. Implementation Status . . . . . . . . . . . . . . . . . . . . 15 107 9.1. Authors' Implementation . . . . . . . . . . . . . . . . . 15 108 9.2. Shane Kerr's Implementation . . . . . . . . . . . . . . . 15 109 10. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 16 110 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 111 11.1. Normative References . . . . . . . . . . . . . . . . . . 19 112 11.2. Informative References . . . . . . . . . . . . . . . . . 20 113 Appendix A. Example Zones With Digests . . . . . . . . . . . . . 22 114 A.1. Simple EXAMPLE Zone . . . . . . . . . . . . . . . . . . . 22 115 A.2. Complex EXAMPLE Zone . . . . . . . . . . . . . . . . . . 22 116 A.3. EXAMPLE Zone with multiple digests . . . . . . . . . . . 23 117 A.4. The URI.ARPA Zone . . . . . . . . . . . . . . . . . . . . 24 118 A.5. The ROOT-SERVERS.NET Zone . . . . . . . . . . . . . . . . 27 119 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 121 1. Introduction 123 In the DNS, a zone is the collection of authoritative resource 124 records (RRs) sharing a common origin ([RFC7719]). Zones are often 125 stored as files on disk in the so-called master file format 126 [RFC1034]. Zones are generally distributed among name servers using 127 the AXFR [RFC5936], and IXFR [RFC1995] protocols. Zone files can 128 also be distributed outside of the DNS, with such protocols as FTP, 129 HTTP, rsync, and even via email. Currently there is no standard way 130 to verify the authenticity of a stand-alone zone. 132 This document introduces a new RR type that serves as a cryptographic 133 message digest of the data in a zone. It allows a receiver of the 134 zone to verify the zone's authenticity, especially when used in 135 combination with DNSSEC. This technique makes the digest a part of 136 the zone itself, allowing verification the zone as a whole, no matter 137 how it is transmitted. Furthermore, the digest is based on the wire 138 format of zone data. Thus, it is independent of presentation format, 139 such as changes in whitespace, capitalization, and comments. 141 DNSSEC provides three strong security guarantees relevant to this 142 protocol: 144 1. whether or not to expect DNSSEC records in the zone, 145 2. whether or not to expect a ZONEMD record in a signed zone, and 147 3. whether or not the ZONEMD record has been altered since it was 148 signed. 150 This specification is OPTIONAL to implement by both publishers and 151 consumers of zone data. 153 1.1. Motivation 155 The motivation for this protocol enhancement is the desire for the 156 ability to verify the authenticity of a stand-alone zone, regardless 157 of how it is transmitted. A consumer of zone data should be able to 158 verify that the data is as-published by the zone operator. 160 One approach to preventing data tampering and corruption is to secure 161 the distribution channel. The DNS has a number of features that can 162 already be used for channel security. Perhaps the most widely used 163 is DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared 164 secret keys and a message digest to protect individual query and 165 response messages. It is generally used to authenticate and validate 166 UPDATE [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages. 168 DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another 169 protocol extension designed to authenticate individual DNS 170 transactions. Whereas SIG records were originally designed to cover 171 specific RR types, SIG(0) is used to sign an entire DNS message. 172 Unlike TSIG, SIG(0) uses public key cryptography rather than shared 173 secrets. 175 The Transport Layer Security protocol suite is also designed to 176 provide channel security. One can easily imagine the distribution of 177 zones over HTTPS-enabled web servers, as well as DNS-over-HTTPS 178 [dns-over-https], and perhaps even a future version of DNS-over-TLS 179 ([RFC7858]). 181 Unfortunately, the protections provided by these channel security 182 techniques are (in practice) ephemeral and are not retained after the 183 data transfer is complete. They can ensure that the client receives 184 the data from the expected server, and that the data sent by the 185 server is not modified during transmission. However, they do not 186 guarantee that the server transmits the data as originally published, 187 and do not provide any methods to verify data that is read after 188 transmission is complete. For example, a name server loading saved 189 zone data upon restart cannot guarantee that the on-disk data has not 190 been modified. For these reasons, it is preferable to secure the 191 data itself. 193 Why not simply rely on DNSSEC, which provides certain data security 194 guarantees? Certainly for zones that are signed, a recipient could 195 validate all of the signed RRSets. Additionally, denial-of-existence 196 records can prove that RRSets have not been added or removed. 197 However, not all RRSets in a zone are signed. The design of DNSSEC 198 stipulates that delegations (non-apex NS records) are not signed, and 199 neither are any glue records. Thus, changes to delegation and glue 200 records cannot be detected by DNSSEC alone. Furthermore, zones that 201 employ NSEC3 with opt-out are susceptible to the removal or addition 202 of names between the signed nodes. Whereas DNSSEC is primarily 203 designed to protect consumers of DNS response messages, this protocol 204 is designed to protect consumers of zones. 206 There are existing tools and protocols that provide data security, 207 such as OpenPGP [RFC4880] and S/MIME [RFC3851]. In fact, the 208 internic.net site publishes PGP signatures along side the root zone 209 and other files available there. However, this is a detached 210 signature with no strong association to the corresponding zone file 211 other than its timestamp. Non-detached signatures are, of course, 212 possible, but these necessarily change the format of the file being 213 distributed. That is, a zone signed with OpenPGP or S/MIME no longer 214 looks like a DNS zone and could not directly be loaded into a name 215 server. Once loaded the signature data is lost, so it does not 216 survive further propagation. 218 It seems the desire for data security in DNS zones was envisioned as 219 far back as 1997. [RFC2065] is an obsoleted specification of the 220 first generation DNSSEC Security Extensions. It describes a zone 221 transfer signature, aka AXFR SIG, which is similar to the technique 222 proposed by this document. That is, it proposes ordering all 223 (signed) RRSets in a zone, hashing their contents, and then signing 224 the zone hash. The AXFR SIG is described only for use during zone 225 transfers. It did not postulate the need to validate zone data 226 distributed outside of the DNS. Furthermore, its successor, 227 [RFC2535], omits the AXFR SIG, while at the same time introducing an 228 IXFR SIG. 230 1.2. Design Overview 232 This document introduces a new Resource Record type designed to 233 convey a message digest of the content of a zone. The digest is 234 calculated at the time of zone publication. Ideally the zone is 235 signed with DNSSEC to guarantee that any modifications of the digest 236 can be detected. The procedures for digest calculation and DNSSEC 237 signing are similar (i.e., both require the same ordering of RRs) and 238 can be done in parallel. 240 The zone digest is designed to be used on zones that are relatively 241 stable and have infrequent updates. As currently specified, the 242 digest is re-calculated over the entire zone content each time. This 243 specification does not provide an efficient mechanism for incremental 244 updates of zone data. It does, however, include a field in the 245 ZONEMD record intended for future work to support incremental zone 246 digest algorithms (e.g. using Merkle trees). 248 It is expected that verification of a zone digest would be 249 implemented in name server software. That is, a name server can 250 verify the zone data it was given and refuse to serve a zone which 251 fails verification. For signed zones, the name server needs a trust 252 anchor to perform DNSSEC validation. For signed non-root zones, the 253 name server may need to send queries to validate a chain-of-trust. 254 Digest verification could also be performed externally. 256 1.3. Use Cases 258 1.3.1. Root Zone 260 The root zone [InterNIC] is one of the most widely distributed DNS 261 zone on the Internet, served by 930 separate instances [RootServers] 262 at the time of this writing. Additionally, many organizations 263 configure their own name servers to serve the root zone locally. 264 Reasons for doing so include privacy and reduced access time. 265 [RFC7706] describes one, but not the only, way to do this. As the 266 root zone spreads beyond its traditional deployment boundaries, the 267 need for verification of the completeness of the zone contents 268 becomes increasingly important. 270 1.3.2. Providers, Secondaries, and Anycast 272 Since its very early days, the developers of the DNS recognized the 273 importance of secondary name servers and service diversity. However, 274 they may not have anticipated the complexity of modern DNS service 275 provisioning which can include multiple third-party providers and 276 hundreds of anycast instances. Instead of a simple primary-to- 277 secondary zone distribution system, today it is possible to have 278 multiple levels, multiple parties, and multiple protocols involved in 279 the distribution of zone data. This complexity introduces new places 280 for problems to arise. The zone digest protects the integrity of 281 data that flows through such systems. 283 1.3.3. Response Policy Zones 285 DNS Response Policy Zones is "a method of expressing DNS response 286 policy information inside specially constructed DNS zones..." [RPZ]. 287 A number of companies provide RPZ feeds, which can be consumed by 288 name server and firewall products. Since these are zones, AXFR is 289 often, but not necessarily used for transmission. While RPZ zones 290 can certainly be signed with DNSSEC, the data is not queried 291 directly, and would not be subject to DNSSEC validation. 293 1.3.4. Centralized Zone Data Service 295 ICANN operates the Centralized Zone Data Service [CZDS], which is a 296 repository of top-level domain zone files. Users request access to 297 the system, and to individual zones, and are then able to download 298 zone data for certain uses. Adding a zone digest to these would 299 provide CZDS users with assurances that the data has not been 300 modified. Note that ZONEMD could be added to CZDS zone data 301 independently of the zone served by production name servers. 303 1.3.5. General Purpose Comparison Check 305 Since the zone digest does not depend on presentation format, it 306 could be used to compare multiple copies of a zone received from 307 different sources, or copies generated by different processes. 309 1.4. Requirements Language 311 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 312 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 313 "OPTIONAL" in this document are to be interpreted as described in BCP 314 14 [RFC2119] [RFC8174] when, and only when, they appear in all 315 capitals, as shown here. 317 2. The ZONEMD Resource Record 319 This section describes the ZONEMD Resource Record, including its 320 fields, wire format, and presentation format. The Type value for the 321 ZONEMD RR is 63. The ZONEMD RR is class independent. The RDATA of 322 the resource record consists of four fields: Serial, Digest Type, 323 Parameter, and Digest. 325 This specification utilizes ZONEMD RRs located at the zone apex. 326 Non-apex ZONEMD RRs are not forbidden, but have no meaning in this 327 specification. 329 A zone MAY contain multiple ZONEMD RRs to support algorithm agility 330 [RFC7696] and rollovers. Each ZONEMD RR MUST specify a unique Digest 331 Type and Parameter tuple. It is RECOMMENDED that a zone include only 332 one ZONEMD RR, unless the zone publisher is in the process of 333 transitioning to a new Digest Type. 335 2.1. ZONEMD RDATA Wire Format 337 The ZONEMD RDATA wire format is encoded as follows: 339 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 340 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 1 341 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 | Serial | 343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 344 | Digest Type | Parameter | | 345 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 346 | Digest | 347 / / 348 / / 349 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 351 2.1.1. The Serial Field 353 The Serial field is a 32-bit unsigned integer in network order. It 354 is equal to the serial number from the zone's SOA record ([RFC1035] 355 section 3.3.13) for which the zone digest was generated. 357 The zone's serial number is included here in order to make DNS 358 response messages of type ZONEMD meaningful. Without the serial 359 number, a stand-alone ZONEMD digest has no association to any 360 particular instance of a zone. 362 2.1.2. The Digest Type Field 364 The Digest Type field is an 8-bit unsigned integer that identifies 365 the algorithm used to construct the digest. 367 At the time of this writing, SHA384-SIMPLE, with value 1, is the only 368 standardized Digest Type defined for ZONEMD records. The Digest Type 369 registry is further described in Section 5. 371 Digest Type values 240-254 are allocated for Private Use as described 372 in [RFC8126]. 374 2.1.3. The Parameter Field 376 The Parameter field is an 8-bit unsigned integer whose meaning 377 depends on the Digest Type in use. For SHA384-SIMPLE, the Parameter 378 field plays no role in digest calculation or verification. 380 2.1.4. The Digest Field 382 The Digest field is a variable-length sequence of octets containing 383 the message digest. The Digest field MUST NOT be empty. Section 3 384 describes how to calculate the digest for a zone. Section 4 385 describes how to use the digest to verify the contents of a zone. 387 2.2. ZONEMD Presentation Format 389 The presentation format of the RDATA portion is as follows: 391 The Serial field MUST be represented as an unsigned decimal integer. 393 The Digest Type field MUST be represented as an unsigned decimal 394 integer. 396 The Parameter field MUST be represented as an unsigned decimal 397 integer. 399 The Digest MUST be represented as a sequence of case-insensitive 400 hexadecimal digits. Whitespace is allowed within the hexadecimal 401 text. 403 2.3. ZONEMD Example 405 The following example shows a ZONEMD RR. 407 example.com. 86400 IN ZONEMD 2018031500 1 0 ( 408 FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE 409 7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE ) 411 3. Calculating the Digest 413 3.1. Canonical Format and Ordering 415 Calculation of the zone digest REQUIRES RRs to be processed in a 416 consistent format and ordering. Correct ordering depends on (1) 417 ordering of owner names, (2) ordering of RRSets with the same owner 418 name, and (3) ordering of RRs within an RRSet. 420 This specification adopts DNSSEC's canonical ordering for names 421 (Section 6.1 of [RFC4034]), and canonical ordering for RRs within an 422 RRSet (Section 6.3 of [RFC4034]). It also adopts DNSSEC's canonical 423 RR form (Section 6.2 of [RFC4034]). However, since DNSSEC does not 424 define a canonical ordering for RRSets having the same owner name, 425 that ordering is defined here. 427 3.1.1. Order of RRSets Having the Same Owner Name 429 For the purposes of calculating the zone digest, RRSets having the 430 same owner name MUST be numerically ordered, in ascending order, by 431 their numeric RR TYPE. 433 3.1.2. Duplicate RRs 435 As stated in Section 5 of [RFC2181], it is meaningless for a zone to 436 have multiple RRs with equal owner name, class, type, and RDATA. In 437 the interest of consistency and interoperability, such duplicate RRs 438 MUST NOT be included in the calculation of a zone digest. 440 3.2. Add ZONEMD Placeholder 442 In preparation for calculating the zone digest, any existing ZONEMD 443 records at the zone apex MUST first be deleted. 445 Prior to calculation of the digest, and prior to signing with DNSSEC, 446 a placeholder ZONEMD record MUST be added to the zone apex. This 447 serves two purposes: (1) it allows the digest to cover the Serial, 448 Digest Type, and Parameter field values, and (2) ensures that 449 appropriate denial-of-existence (NSEC, NSEC3) records are created if 450 the zone is signed with DNSSEC. 452 It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of 453 the SOA. 455 In the placeholder record, the Serial field MUST be set to the 456 current SOA Serial. The Digest Type field MUST be set to the value 457 for the chosen digest algorithm. The Parameter field is set to a 458 value whose meaning depends on the Digest Type. The Digest field 459 MUST be set to all zeroes and of length appropriate for the chosen 460 digest algorithm. 462 If multiple digests are to be published in the zone, e.g., during an 463 algorithm rollover, there MUST be one placeholder record for each 464 Digest Type. 466 3.3. Optionally Sign the Zone 468 Following addition of placeholder records, the zone MAY be signed 469 with DNSSEC. Note that when the digest calculation is complete, and 470 the ZONEMD record is updated, the signature(s) for the ZONEMD RRSet 471 MUST be recalculated and updated as well. Therefore, the signer is 472 not required to calculate a signature over the placeholder record at 473 this step in the process, but it is harmless to do so. 475 3.4. Calculate the Digest 477 The digest calculation details vary depending upon the Digest Type. 478 This document describes digest calculation for SHA384-SIMPLE only. 479 Digest calculation for additional types may be defined in future 480 updates to this document. 482 3.4.1. SHA384-SIMPLE Calculation 484 For SHA384-SIMPLE, the digest is calculated over the zone as a whole. 485 This means that a change to a single RR in the zone requires 486 iterating over all RRs in the zone to recalculate the digest. 487 SHA384-SIMPLE is good for zones that are small and/or stable, but 488 probably not good for zones that are large and/or dynamic. 490 The Parameter field is not used in the calculation of SHA384-SIMPLE 491 zone digests. The Parameter field SHOULD be set to zero in 492 SHA384-SIMPLE placeholder records. 494 The zone digest is calculated by concatenating the canonical on-the- 495 wire form (without name compression) of all RRs in the zone, in the 496 order described above, subject to the inclusion/exclusion rules 497 described below, and then applying the SHA384 digest algorithm 498 [RFC6605]: 500 digest = SHA384( RR(1) | RR(2) | RR(3) | ... ) 502 where "|" denotes concatenation, and 504 RR(i) = owner | type | class | TTL | RDATA length | RDATA 506 3.4.2. Inclusion/Exclusion Rules 508 When calculating the digest, the following inclusion/exclusion rules 509 apply: 511 o All records in the zone, including glue records, MUST be included. 513 o Occluded data ([RFC5936] Section 3.5) MUST be included. 515 o Duplicate RRs with equal owner, class, type, and RDATA MUST NOT be 516 included. 518 o The placeholder ZONEMD RR(s) MUST be included. 520 o If the zone is signed, DNSSEC RRs MUST be included, except: 522 o The RRSIG covering ZONEMD MUST NOT be included because the RRSIG 523 will be updated after all digests have been calculated. 525 3.5. Update ZONEMD RR 527 Once a zone digest has been calculated, its value is then copied to 528 the Digest field of the placeholder ZONEMD record. Repeat for each 529 digest if multiple digests are to be published. 531 If the zone is signed with DNSSEC, the appropriate RRSIG records 532 covering the ZONEMD RRSet MUST then be added or updated. Because the 533 ZONEMD placeholder was added prior to signing, the zone will already 534 have the appropriate denial-of-existence (NSEC, NSEC3) records. 536 Some implementations of incremental DNSSEC signing might update the 537 zone's serial number for each resigning. However, to preserve the 538 calculated digest, generation of the ZONEMD signature at this time 539 MUST NOT also result in a change of the SOA serial number. 541 4. Verifying Zone Digest 543 The recipient of a zone that has a ZONEMD RR can verify the zone by 544 calculating the digest as follows: 546 1. The verifier SHOULD first determine whether or not to expect 547 DNSSEC records in the zone. This can be done by examining 548 locally configured trust anchors, or querying for (and 549 validating) DS RRs in the parent zone. For zones that are 550 provably insecure, digest validation continues at step 4 below. 552 2. For zones that are provably secure, the existence of the apex 553 ZONEMD record MUST be verified. If the ZONEMD record provably 554 does not exist, digest verification cannot be done. If the 555 ZONEMD record does provably exist, but is not found in the zone, 556 digest verification MUST NOT be considered successful. 558 3. For zones that are provably secure, the SOA and ZONEMD RRSets 559 MUST have valid signatures, chaining up to a trust anchor. If 560 DNSSEC validation of the SOA or ZONEMD records fails, digest 561 verification MUST NOT be considered successful. 563 4. If the ZONEMD RRSet contains more than one RR with the same 564 Digest Type and Parameter, digest verification MUST NOT be 565 considered successful. 567 5. The SOA Serial field MUST exactly match the ZONEMD Serial field. 568 If the fields to not match, digest verification MUST NOT be 569 considered successful. 571 6. The ZONEMD Digest Type field MUST be checked. If the verifier 572 does not support the given digest type, it SHOULD report that 573 the zone digest could not be verified due to an unsupported 574 algorithm. 576 7. The received Digest Type and Digest values are copied to a 577 temporary location. 579 8. The ZONEMD RR's RDATA is reset to the placeholder values 580 described in Section 3.2. 582 9. The zone digest is computed over the zone data as described in 583 Section 3.4. 585 10. The calculated digest is compared to the received digest stored 586 in the temporary location. If the two digest values match, 587 verification is considered successful. Otherwise, verification 588 MUST NOT be considered successful. 590 11. The ZONEMD RR's RDATA is reset to the received Digest Type and 591 Digest stored in the temporary location. Thus, any downstream 592 clients can similarly verify the zone. 594 4.1. Verifying Multiple Digests 596 If multiple digests are present in the zone, e.g., during an 597 algorithm rollover, a match using any one of the recipient's 598 supported Digest Type algorithms is sufficient to verify the zone. 600 5. IANA Considerations 602 5.1. ZONEMD RRtype 604 This document defines a new DNS RR type, ZONEMD, whose value 63 has 605 been allocated by IANA from the "Resource Record (RR) TYPEs" 606 subregistry of the "Domain Name System (DNS) Parameters" registry: 608 Type: ZONEMD 610 Value: 63 612 Meaning: Message Digest Over Zone Data 614 Reference: This document 616 5.2. ZONEMD Digest Type 618 This document asks IANA to create a new "ZONEMD Digest Types" 619 registry with initial contents as follows: 621 +---------+-----------------+---------------+-----------+-----------+ 622 | Value | Description | Mnemonic | Status | Reference | 623 +---------+-----------------+---------------+-----------+-----------+ 624 | 1 | SHA384 simple | SHA384-SIMPLE | Mandatory | This | 625 | | zone digest | | | document | 626 | 240-254 | Private Use | - | - | [RFC8126] | 627 +---------+-----------------+---------------+-----------+-----------+ 629 Table 1: ZONEMD Digest Types 631 6. Security Considerations 633 6.1. Attacks Against the Zone Digest 635 The zone digest allows the receiver to verify that the zone contents 636 haven't been modified since the zone was generated/published. 637 Verification is strongest when the zone is also signed with DNSSEC. 638 An attacker, whose goal is to modify zone content before it is used 639 by the victim, may consider a number of different approaches. 641 The attacker might perform a downgrade attack to an unsigned zone. 642 This is why Section 4 RECOMMENDS that the verifier determine whether 643 or not to expect DNSSEC signatures for the zone in step 1. 645 The attacker might perform a downgrade attack by removing the ZONEMD 646 record. This is why Section 4 REQUIRES that the verifier checks 647 DNSSEC denial-of-existence proofs in step 2. 649 The attacker might alter the Digest Type or Digest fields of the 650 ZONEMD record. Such modifications are detectable only with DNSSEC 651 validation. 653 6.2. Attacks Utilizing the Zone Digest 655 Nothing in this specification prevents clients from making, and 656 servers from responding to, ZONEMD queries. One might consider how 657 well ZONEMD responses could be used in a distributed denial-of- 658 service amplification attack. 660 The ZONEMD RR is moderately sized, much like the DS RR. A single 661 ZONEMD RR contributes approximately 40 to 65 octets to a DNS 662 response, for currently defined digest types. Certainly other query 663 types result in larger amplification effects (i.e., DNSKEY). 665 7. Privacy Considerations 667 This specification has no impacts on user privacy. 669 8. Acknowledgments 671 The authors wish to thank David Blacka, Scott Hollenbeck, and Rick 672 Wilhelm for providing feedback on early drafts of this document. 673 Additionally, they thank Joe Abley, Mark Andrews, Ralph Dolmans, 674 Richard Gibson, Olafur Gudmundsson, Paul Hoffman, Evan Hunt, Shumon 675 Huque, Tatuya Jinmei, Burt Kaliski, Shane Kerr, Matt Larson, John 676 Levine, Ed Lewis, Matt Pounsett, Mukund Sivaraman, Petr Spacek, 677 Ondrej Sury, Willem Toorop, Florian Weimer, Tim Wicinksi, Wouter 678 Wijngarrds, Paul Wouters, and other members of the dnsop working 679 group for their input. 681 9. Implementation Status 683 9.1. Authors' Implementation 685 The authors have an open source implementation in C, using the ldns 686 library [ldns-zone-digest]. This implementation is able to perform 687 the following functions: 689 o Read an input zone and output a zone with the ZONEMD placeholder. 691 o Compute zone digest over signed zone and update the ZONEMD record. 693 o Re-compute DNSSEC signature over the ZONEMD record. 695 o Verify the zone digest from an input zone. 697 This implementation does not: 699 o Perform DNSSEC validation of the ZONEMD record during 700 verification. 702 9.2. Shane Kerr's Implementation 704 Shane Kerr wrote an implementation of this specification during the 705 IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in 706 Python and is able to perform the following functions: 708 o Read an input zone and a output zone with ZONEMD record. 710 o Verify the zone digest from an input zone. 712 o Output the ZONEMD record in its defined presentation format. 714 This implementation does not: 716 o Re-compute DNSSEC signature over the ZONEMD record. 718 o Perform DNSSEC validation of the ZONEMD record. 720 10. Change Log 722 RFC Editor: Please remove this section. 724 This section lists substantial changes to the document as it is being 725 worked on. 727 From -00 to -01: 729 o Removed requirement to sort by RR CLASS. 731 o Added Kumari and Hardaker as coauthors. 733 o Added Change Log section. 735 o Minor clarifications and grammatical edits. 737 From -01 to -02: 739 o Emphasize desire for data security over channel security. 741 o Expanded motivation into its own subsection. 743 o Removed discussion topic whether or not to include serial in 744 ZONEMD. 746 o Clarified that a zone's NS records always sort before the SOA 747 record. 749 o Clarified that all records in the zone must are digested, except 750 as specified in the exclusion rules. 752 o Added for discussion out-of-zone and occluded records. 754 o Clarified that update of ZONEMD signature must not cause a serial 755 number change. 757 o Added persons to acknowledgments. 759 From -02 to -03: 761 o Added recommendation to set ZONEMD TTL to SOA TTL. 763 o Clarified that digest input uses uncompressed names. 765 o Updated Implementations section. 767 o Changed intended status from Standards Track to Experimental and 768 added Scope of Experiment section. 770 o Updated Motivation, Introduction, and Design Overview sections in 771 response to working group discussion. 773 o Gave ZONEMD digest types their own status, separate from DS digest 774 types. Request IANA to create a registry. 776 o Added Reserved field for future work supporting dynamic updates. 778 o Be more rigorous about having just ONE ZONEMD record in the zone. 780 o Expanded use cases. 782 From -03 to -04: 784 o Added an appendix with example zones and digests. 786 o Clarified that only apex ZONEMD RRs shall be processed. 788 From -04 to -05: 790 o Made SHA384 the only supported ZONEMD digest type. 792 o Disassociated ZONEMD digest types from DS digest types. 794 o Updates to Introduction based on list feedback. 796 o Changed "zone file" to "zone" everywhere. 798 o Restored text about why ZONEMD has a Serial field. 800 o Clarified ordering of RRSets having same owner to be numerically 801 ascending. 803 o Clarified that all duplicate RRs (not just SOA) must be suppressed 804 in digest calculation. 806 o Clarified that the Reserved field must be set to zero and checked 807 for zero in verification. 809 o Clarified that occluded data must be included. 811 o Clarified procedure for verification, using temporary location for 812 received digest. 814 o Explained why Reserved field is 8-bits. 816 o IANA Considerations section now more specific. 818 o Added complex zone to examples. 820 o 822 From -05 to -06: 824 o RR type code 63 was assigned to ZONEMD by IANA. 826 From -06 to -07: 828 o Fixed mistakes in ZONEMD examples. 830 o Added private use Digest Type values 240-254. 832 o Clarified that Digest field must not be empty. 834 From -07 to draft-ietf-dnsop-dns-zone-digest-00: 836 o Adopted by dnsop. 838 o Clarified further that non-apex ZONEMD RRs have no meaning. 840 o Changed "provably [un]signed" to "provably [in]secure". 842 o Allow multiple ZONEMD RRs to support algorithm agility/rollovers. 844 o Describe verification when there are multiple ZONEMD RRs. 846 From -00 to -01: 848 o Simplified requirements around verifying multiple digests. Any 849 one match is sufficient. 851 o Updated implementation notes. 853 o Both implementations produce expected results on examples given in 854 this document. 856 From -01 to -02: 858 o Changed the name of the Reserved field to Parameter. 860 o Changed the name of Digest Type 1 from SHA384 to SHA384-STABLE. 862 o The meaning of the Parameter field now depends on Digest Type. 864 o No longer require Parameter field to be zero in verification. 866 o Updated a rule from earlier versions that said multiple ZONEMD RRs 867 were not allowed. 869 From -02 to -03: 871 o Changed the name of Digest Type 1 from SHA384-STABLE to 872 SHA384-SIMPLE. 874 o Changed document status from Experimental to Standards Track. 876 o Removed Scope of Experimentation section. 878 11. References 880 11.1. Normative References 882 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 883 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 884 . 886 [RFC1035] Mockapetris, P., "Domain names - implementation and 887 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 888 November 1987, . 890 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 891 Requirement Levels", BCP 14, RFC 2119, 892 DOI 10.17487/RFC2119, March 1997, 893 . 895 [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS 896 Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, 897 . 899 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 900 Rose, "Resource Records for the DNS Security Extensions", 901 RFC 4034, DOI 10.17487/RFC4034, March 2005, 902 . 904 [RFC6605] Hoffman, P. and W. Wijngaards, "Elliptic Curve Digital 905 Signature Algorithm (DSA) for DNSSEC", RFC 6605, 906 DOI 10.17487/RFC6605, April 2012, 907 . 909 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 910 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 911 May 2017, . 913 11.2. Informative References 915 [CZDS] Internet Corporation for Assigned Names and Numbers, 916 "Centralized Zone Data Service", October 2018, 917 . 919 [dns-over-https] 920 Hoffman, P. and P. McManus, "DNS Queries over HTTPS 921 (DoH)", draft-ietf-doh-dns-over-https-12 (work in 922 progress), June 2018, . 925 [InterNIC] 926 ICANN, "InterNIC FTP site", May 2018, 927 . 929 [ldns-zone-digest] 930 Verisign, "Implementation of Message Digests for DNS Zones 931 using the ldns library", July 2018, 932 . 934 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 935 DOI 10.17487/RFC1995, August 1996, 936 . 938 [RFC2065] Eastlake 3rd, D. and C. Kaufman, "Domain Name System 939 Security Extensions", RFC 2065, DOI 10.17487/RFC2065, 940 January 1997, . 942 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 943 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 944 RFC 2136, DOI 10.17487/RFC2136, April 1997, 945 . 947 [RFC2535] Eastlake 3rd, D., "Domain Name System Security 948 Extensions", RFC 2535, DOI 10.17487/RFC2535, March 1999, 949 . 951 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 952 Wellington, "Secret Key Transaction Authentication for DNS 953 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 954 . 956 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 957 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 958 2000, . 960 [RFC3851] Ramsdell, B., Ed., "Secure/Multipurpose Internet Mail 961 Extensions (S/MIME) Version 3.1 Message Specification", 962 RFC 3851, DOI 10.17487/RFC3851, July 2004, 963 . 965 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 966 Thayer, "OpenPGP Message Format", RFC 4880, 967 DOI 10.17487/RFC4880, November 2007, 968 . 970 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 971 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 972 . 974 [RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm 975 Agility and Selecting Mandatory-to-Implement Algorithms", 976 BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015, 977 . 979 [RFC7706] Kumari, W. and P. Hoffman, "Decreasing Access Time to Root 980 Servers by Running One on Loopback", RFC 7706, 981 DOI 10.17487/RFC7706, November 2015, 982 . 984 [RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS 985 Terminology", RFC 7719, DOI 10.17487/RFC7719, December 986 2015, . 988 [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., 989 and P. Hoffman, "Specification for DNS over Transport 990 Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 991 2016, . 993 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 994 Writing an IANA Considerations Section in RFCs", BCP 26, 995 RFC 8126, DOI 10.17487/RFC8126, June 2017, 996 . 998 [RootServers] 999 Root Server Operators, "Root Server Technical Operations", 1000 July 2018, . 1002 [RPZ] Vixie, P. and V. Schryver, "DNS Response Policy Zones 1003 (RPZ)", draft-vixie-dnsop-dns-rpz-00 (work in progress), 1004 June 2018, . 1007 [ZoneDigestHackathon] 1008 Kerr, S., "Prototype implementation of ZONEMD for the IETF 1009 102 hackathon in Python", July 2018, 1010 . 1012 Appendix A. Example Zones With Digests 1014 This appendix contains example zones with accurate ZONEMD records. 1015 These can be used to verify an implementation of the zone digest 1016 protocol. 1018 A.1. Simple EXAMPLE Zone 1020 Here, the EXAMPLE zone contains an SOA record, NS and glue records, 1021 and a ZONEMD record. 1023 example. 86400 IN SOA ns1 admin 2018031900 ( 1024 1800 900 604800 86400 ) 1025 86400 IN NS ns1 1026 86400 IN NS ns2 1027 86400 IN ZONEMD 2018031900 1 0 ( 1028 379ec2587d4fff35 1029 0062b9385a641476 1030 6f9c028e8cf09d8a 1031 7965537a68a2f149 1032 4e1c151f8cf6be05 1033 5bef4f27e6a87b13 ) 1034 ns1 3600 IN A 127.0.0.1 1035 ns2 3600 IN AAAA ::1 1037 A.2. Complex EXAMPLE Zone 1039 Here, the EXAMPLE zone contains duplicate RRs, and an occluded RR, 1040 and one out-of-zone RR. 1042 example. 86400 IN SOA ns1 admin 2018031900 ( 1043 1800 900 604800 86400 ) 1044 86400 IN NS ns1 1045 86400 IN NS ns2 1046 86400 IN ZONEMD 2018031900 1 0 ( 1047 c36e77eafdb7f3f6 1048 dcfac8bca1121e17 1049 2a7b57db2c88409a 1050 5c3d9247ba72b759 1051 6c735c1a76fc817a 1052 ad5c834f5a4bce16 ) 1053 ns1 3600 IN A 127.0.0.1 1054 ns2 3600 IN AAAA ::1 1055 occluded.sub 7200 IN TXT "I'm occluded but must be digested" 1056 sub 7200 IN NS ns1 1057 duplicate 300 IN TXT "I must be digested just once" 1058 duplicate 300 IN TXT "I must be digested just once" 1059 foo.test. 555 IN TXT "out-of-zone data must be excluded" 1060 non-apex 900 IN ZONEMD 2018031900 1 0 ( 1061 616c6c6f77656420 1062 6275742069676e6f 1063 7265642e20616c6c 1064 6f77656420627574 1065 2069676e6f726564 1066 2e20616c6c6f7765 ) 1068 A.3. EXAMPLE Zone with multiple digests 1070 Here, the EXAMPLE zone contains multiple ZONEMD records. Since only 1071 one Digest Type is defined at this time (SHA384-SIMPLE), this example 1072 utilizes additional ZONEMD records with Digest Type values in the 1073 private range (240-254). These additional private-range digests are 1074 not verifiable, but note that their other fields (Serial, Parameter, 1075 Digest Type) are included in the calculation of all ZONEMD digests. 1077 example. 86400 IN SOA ns1 admin 2018031900 ( 1078 1800 900 604800 86400 ) 1079 example. 86400 IN NS ns1.example. 1080 example. 86400 IN NS ns2.example. 1081 example. 86400 IN ZONEMD 2018031900 1 0 ( 1082 c0218e8eeb4f0275 1083 d54c0e5ce7791f4d 1084 23742b4756708d50 1085 d7121a11d434baa8 1086 f869ebbb071a4bbb 1087 0457c87870bc8cdd ) 1088 example. 86400 IN ZONEMD 2018031900 240 0 ( 1089 e2d523f654b9422a 1090 96c5a8f44607bbee ) 1091 example. 86400 IN ZONEMD 2018031900 241 0 ( 1092 5732dd91240611f8 1093 314adb6b4769bdd2 ) 1094 example. 86400 IN ZONEMD 2018031900 242 0 ( 1095 7c32e06779315c7d 1096 81ba8c72f5cf9116 1097 496b6395 ) 1098 example. 86400 IN ZONEMD 2018031900 243 0 ( 1099 183770af4a629f80 1100 2e674e305b8d0d11 1101 3dfe0837 ) 1102 example. 86400 IN ZONEMD 2018031900 244 0 ( 1103 e1846540e33a9e41 1104 89792d18d5d131f6 1105 05fc283e ) 1106 ns1.example. 3600 IN A 127.0.0.1 1107 ns2.example. 86400 IN TXT "This example has multiple digests" 1108 ns2.example. 3600 IN AAAA ::1 1110 A.4. The URI.ARPA Zone 1112 The URI.ARPA zone retrieved 2018-10-21. 1114 ; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr 1115 ; (2 servers found) 1116 ;; global options: +cmd 1117 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1118 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1119 uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 ( 1120 20181028142623 20181007205525 47155 uri.arpa. 1121 eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi 1122 /pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e 1123 HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= ) 1124 uri.arpa. 86400 IN RRSIG NS 8 2 86400 ( 1125 20181028172020 20181007175821 47155 uri.arpa. 1126 ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln 1127 4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF 1128 Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= ) 1129 uri.arpa. 600 IN RRSIG MX 8 2 600 ( 1130 20181028170556 20181007175821 47155 uri.arpa. 1131 e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t 1132 lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK 1133 A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= ) 1134 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1135 20181028152832 20181007175821 15796 uri.arpa. 1136 nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286 1137 XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V 1138 chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR 1139 6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B 1140 dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd 1141 uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk 1142 5R0A1w== ) 1143 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1144 20181028152832 20181007175821 55480 uri.arpa. 1145 lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X 1146 nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV 1147 63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj 1148 2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75 1149 WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R 1150 PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA 1151 1HeBfw== ) 1152 uri.arpa. 3600 IN RRSIG SOA 8 2 3600 ( 1153 20181029114753 20181008222815 47155 uri.arpa. 1154 qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2 1155 Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu 1156 9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= ) 1157 uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA ( 1158 MX RRSIG NSEC DNSKEY ) 1159 uri.arpa. 86400 IN NS a.iana-servers.net. 1160 uri.arpa. 86400 IN NS b.iana-servers.net. 1161 uri.arpa. 86400 IN NS c.iana-servers.net. 1162 uri.arpa. 86400 IN NS ns2.lacnic.net. 1163 uri.arpa. 86400 IN NS sec3.apnic.net. 1164 uri.arpa. 600 IN MX 10 pechora.icann.org. 1165 uri.arpa. 3600 IN DNSKEY 256 3 8 ( 1166 AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK 1167 uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL 1168 Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx 1169 SdJjlH0B ) 1170 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1171 AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY 1172 cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc 1173 3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/ 1174 Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9 1175 iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5 1176 ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt 1177 l3wpbp+Wpm8= ) 1178 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1179 AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR 1180 wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD 1181 FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG 1182 mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU 1183 7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3 1184 e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0 1185 xmJVvNQlwdE= ) 1186 ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1187 20181028080856 20181007175821 47155 uri.arpa. 1188 HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9 1189 jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP 1190 Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= ) 1191 ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1192 20181028103644 20181007205525 47155 uri.arpa. 1193 WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0 1194 9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5 1195 YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= ) 1196 ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR ( 1197 RRSIG NSEC ) 1198 ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1199 "!^ftp://([^:/?#]*).*$!\\1!i" . ) 1200 http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1201 20181029010647 20181007175821 47155 uri.arpa. 1202 U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE 1203 H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+ 1204 ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= ) 1205 http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1206 20181029011815 20181007205525 47155 uri.arpa. 1207 T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F 1208 Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0 1209 RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= ) 1210 http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR ( 1211 RRSIG NSEC ) 1212 http.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1213 "!^http://([^:/?#]*).*$!\\1!i" . ) 1214 mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1215 20181028110727 20181007175821 47155 uri.arpa. 1216 GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/ 1217 IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl 1218 fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= ) 1219 mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1220 20181028141825 20181007205525 47155 uri.arpa. 1222 MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF 1223 j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg 1224 916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= ) 1225 mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR ( 1226 RRSIG NSEC ) 1227 mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1228 "!^mailto:(.*)@(.*)$!\\2!i" . ) 1229 urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1230 20181028123243 20181007175821 47155 uri.arpa. 1231 Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe 1232 UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9 1233 DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= ) 1234 urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1235 20181029071816 20181007205525 47155 uri.arpa. 1236 ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS 1237 D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW 1238 BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= ) 1239 urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG ( 1240 NSEC ) 1241 urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1242 "/urn:([^:]+)/\\1/i" . ) 1243 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1244 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1245 ;; Query time: 66 msec 1246 ;; SERVER: 192.0.32.132#53(192.0.32.132) 1247 ;; WHEN: Sun Oct 21 20:39:28 UTC 2018 1248 ;; XFR size: 34 records (messages 1, bytes 3941) 1249 uri.arpa. 3600 IN ZONEMD 2018100702 1 0 ( 1250 e4de6ed36e5d95706756932fae3ecbc6aeb76e16ce486a5553c7e4 1251 c9974d03323e7cd39ccc5e70e797179633f4007bad ) 1253 A.5. The ROOT-SERVERS.NET Zone 1255 The ROOT-SERVERS.NET zone retreived 2018-10-21. 1257 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1258 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1259 root-servers.net. 3600000 IN NS a.root-servers.net. 1260 root-servers.net. 3600000 IN NS b.root-servers.net. 1261 root-servers.net. 3600000 IN NS c.root-servers.net. 1262 root-servers.net. 3600000 IN NS d.root-servers.net. 1263 root-servers.net. 3600000 IN NS e.root-servers.net. 1264 root-servers.net. 3600000 IN NS f.root-servers.net. 1265 root-servers.net. 3600000 IN NS g.root-servers.net. 1266 root-servers.net. 3600000 IN NS h.root-servers.net. 1267 root-servers.net. 3600000 IN NS i.root-servers.net. 1268 root-servers.net. 3600000 IN NS j.root-servers.net. 1269 root-servers.net. 3600000 IN NS k.root-servers.net. 1270 root-servers.net. 3600000 IN NS l.root-servers.net. 1271 root-servers.net. 3600000 IN NS m.root-servers.net. 1272 a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30 1273 a.root-servers.net. 3600000 IN A 198.41.0.4 1274 b.root-servers.net. 3600000 IN MX 20 mail.isi.edu. 1275 b.root-servers.net. 3600000 IN AAAA 2001:500:200::b 1276 b.root-servers.net. 3600000 IN A 199.9.14.201 1277 c.root-servers.net. 3600000 IN AAAA 2001:500:2::c 1278 c.root-servers.net. 3600000 IN A 192.33.4.12 1279 d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d 1280 d.root-servers.net. 3600000 IN A 199.7.91.13 1281 e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e 1282 e.root-servers.net. 3600000 IN A 192.203.230.10 1283 f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f 1284 f.root-servers.net. 3600000 IN A 192.5.5.241 1285 g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d 1286 g.root-servers.net. 3600000 IN A 192.112.36.4 1287 h.root-servers.net. 3600000 IN AAAA 2001:500:1::53 1288 h.root-servers.net. 3600000 IN A 198.97.190.53 1289 i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org. 1290 i.root-servers.net. 3600000 IN AAAA 2001:7fe::53 1291 i.root-servers.net. 3600000 IN A 192.36.148.17 1292 j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30 1293 j.root-servers.net. 3600000 IN A 192.58.128.30 1294 k.root-servers.net. 3600000 IN AAAA 2001:7fd::1 1295 k.root-servers.net. 3600000 IN A 193.0.14.129 1296 l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42 1297 l.root-servers.net. 3600000 IN A 199.7.83.42 1298 m.root-servers.net. 3600000 IN AAAA 2001:dc3::35 1299 m.root-servers.net. 3600000 IN A 202.12.27.33 1300 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1301 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1302 root-servers.net. 3600000 IN ZONEMD 2018091100 1 0 ( 1303 0c1839d86088062868c1ed79aed6a301dc7b08b02ba2f67cbc62edd4a0 1304 291f4132b8840da47ddab4401cc9088d04a14a ) 1306 Authors' Addresses 1308 Duane Wessels 1309 Verisign 1310 12061 Bluemont Way 1311 Reston, VA 20190 1313 Phone: +1 703 948-3200 1314 Email: dwessels@verisign.com 1315 URI: http://verisign.com 1317 Piet Barber 1318 Verisign 1319 12061 Bluemont Way 1320 Reston, VA 20190 1322 Phone: +1 703 948-3200 1323 Email: pbarber@verisign.com 1324 URI: http://verisign.com 1326 Matt Weinberg 1327 Verisign 1328 12061 Bluemont Way 1329 Reston, VA 20190 1331 Phone: +1 703 948-3200 1332 Email: mweinberg@verisign.com 1333 URI: http://verisign.com 1335 Warren Kumari 1336 Google 1337 1600 Amphitheatre Parkway 1338 Mountain View, CA 94043 1340 Email: warren@kumari.net 1342 Wes Hardaker 1343 USC/ISI 1344 P.O. Box 382 1345 Davis, CA 95617 1347 Email: ietf@hardakers.net