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Checking references for intended status: Experimental ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 2065 (Obsoleted by RFC 2535) -- Obsolete informational reference (is this intentional?): RFC 2535 (Obsoleted by RFC 4033, RFC 4034, RFC 4035) -- Obsolete informational reference (is this intentional?): RFC 2845 (Obsoleted by RFC 8945) -- Obsolete informational reference (is this intentional?): RFC 3851 (Obsoleted by RFC 5751) -- Obsolete informational reference (is this intentional?): RFC 7706 (Obsoleted by RFC 8806) -- Obsolete informational reference (is this intentional?): RFC 7719 (Obsoleted by RFC 8499) Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 7 comments (--). 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: Experimental M. Weinberg 5 Expires: March 8, 2020 Verisign 6 W. Kumari 7 Google 8 W. Hardaker 9 USC/ISI 10 September 5, 2019 12 Message Digest for DNS Zones 13 draft-ietf-dnsop-dns-zone-digest-01 15 Abstract 17 This document describes an experimental protocol and new DNS Resource 18 Record that can be used to provide a message digest over DNS zone 19 data. The ZONEMD Resource Record conveys the message digest data in 20 the zone itself. When a zone publisher includes an ZONEMD record, 21 recipients can verify the zone contents for accuracy and 22 completeness. This provides assurance that received zone data 23 matches published data, regardless of how the zone data has been 24 transmitted and received. 26 ZONEMD is not designed to replace DNSSEC. Whereas DNSSEC protects 27 individual RRSets (DNS data with fine granularity), ZONEMD protects 28 protects a zone's data as a whole, whether consumed by authoritative 29 name servers, recursive name servers, or any other applications. 31 As specified at this time, ZONEMD is not designed for use in large, 32 dynamic zones due to the time and resources required for digest 33 calculation. The ZONEMD record described in this document includes 34 fields reserved for future work to support large, dynamic zones. 36 Status of This Memo 38 This Internet-Draft is submitted in full conformance with the 39 provisions of BCP 78 and BCP 79. 41 Internet-Drafts are working documents of the Internet Engineering 42 Task Force (IETF). Note that other groups may also distribute 43 working documents as Internet-Drafts. The list of current Internet- 44 Drafts is at https://datatracker.ietf.org/drafts/current/. 46 Internet-Drafts are draft documents valid for a maximum of six months 47 and may be updated, replaced, or obsoleted by other documents at any 48 time. It is inappropriate to use Internet-Drafts as reference 49 material or to cite them other than as "work in progress." 51 This Internet-Draft will expire on March 8, 2020. 53 Copyright Notice 55 Copyright (c) 2019 IETF Trust and the persons identified as the 56 document authors. All rights reserved. 58 This document is subject to BCP 78 and the IETF Trust's Legal 59 Provisions Relating to IETF Documents 60 (https://trustee.ietf.org/license-info) in effect on the date of 61 publication of this document. Please review these documents 62 carefully, as they describe your rights and restrictions with respect 63 to this document. Code Components extracted from this document must 64 include Simplified BSD License text as described in Section 4.e of 65 the Trust Legal Provisions and are provided without warranty as 66 described in the Simplified BSD License. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 71 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4 72 1.2. Design Overview . . . . . . . . . . . . . . . . . . . . . 5 73 1.3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 6 74 1.3.1. Root Zone . . . . . . . . . . . . . . . . . . . . . . 6 75 1.3.2. Providers, Secondaries, and Anycast . . . . . . . . . 6 76 1.3.3. Response Policy Zones . . . . . . . . . . . . . . . . 7 77 1.3.4. Centralized Zone Data Service . . . . . . . . . . . . 7 78 1.3.5. General Purpose Comparison Check . . . . . . . . . . 7 79 1.4. Requirements Language . . . . . . . . . . . . . . . . . . 7 80 2. The ZONEMD Resource Record . . . . . . . . . . . . . . . . . 7 81 2.1. ZONEMD RDATA Wire Format . . . . . . . . . . . . . . . . 8 82 2.1.1. The Serial Field . . . . . . . . . . . . . . . . . . 8 83 2.1.2. The Digest Type Field . . . . . . . . . . . . . . . . 8 84 2.1.3. The Reserved Field . . . . . . . . . . . . . . . . . 8 85 2.1.4. The Digest Field . . . . . . . . . . . . . . . . . . 9 86 2.2. ZONEMD Presentation Format . . . . . . . . . . . . . . . 9 87 2.3. ZONEMD Example . . . . . . . . . . . . . . . . . . . . . 9 88 3. Calculating the Digest . . . . . . . . . . . . . . . . . . . 9 89 3.1. Canonical Format and Ordering . . . . . . . . . . . . . . 9 90 3.1.1. Order of RRSets Having the Same Owner Name . . . . . 10 91 3.1.2. Duplicate RRs . . . . . . . . . . . . . . . . . . . . 10 92 3.2. Add ZONEMD Placeholder . . . . . . . . . . . . . . . . . 10 93 3.3. Optionally Sign the Zone . . . . . . . . . . . . . . . . 10 94 3.4. Calculate the Digest . . . . . . . . . . . . . . . . . . 11 95 3.4.1. Inclusion/Exclusion Rules . . . . . . . . . . . . . . 11 97 3.5. Update ZONEMD RR . . . . . . . . . . . . . . . . . . . . 11 98 4. Verifying Zone Message Digest . . . . . . . . . . . . . . . . 12 99 4.1. Verifying Multiple Digests . . . . . . . . . . . . . . . 13 100 5. Scope of Experimentation . . . . . . . . . . . . . . . . . . 13 101 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 102 6.1. ZONEMD RRtype . . . . . . . . . . . . . . . . . . . . . . 13 103 6.2. ZONEMD Digest Type . . . . . . . . . . . . . . . . . . . 14 104 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 105 7.1. Attacks Against the Zone Digest . . . . . . . . . . . . . 14 106 7.2. Attacks Utilizing the Zone Digest . . . . . . . . . . . . 14 107 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 15 108 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 109 10. Implementation Status . . . . . . . . . . . . . . . . . . . . 15 110 10.1. Authors' Implementation . . . . . . . . . . . . . . . . 15 111 10.2. Shane Kerr's Implementation . . . . . . . . . . . . . . 15 112 11. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 16 113 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 114 12.1. Normative References . . . . . . . . . . . . . . . . . . 19 115 12.2. Informative References . . . . . . . . . . . . . . . . . 19 116 Appendix A. Example Zones With Digests . . . . . . . . . . . . . 21 117 A.1. Simple EXAMPLE Zone . . . . . . . . . . . . . . . . . . . 22 118 A.2. Complex EXAMPLE Zone . . . . . . . . . . . . . . . . . . 22 119 A.3. EXAMPLE Zone with multiple digests . . . . . . . . . . . 23 120 A.4. The URI.ARPA Zone . . . . . . . . . . . . . . . . . . . . 24 121 A.5. The ROOT-SERVERS.NET Zone . . . . . . . . . . . . . . . . 27 122 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 124 1. Introduction 126 In the DNS, a zone is the collection of authoritative resource 127 records (RRs) sharing a common origin ([RFC7719]). Zones are often 128 stored as files on disk in the so-called master file format 129 [RFC1034]. Zones are generally distributed among name servers using 130 the AXFR [RFC5936], and IXFR [RFC1995] protocols. Zone files can 131 also be distributed outside of the DNS, with such protocols as FTP, 132 HTTP, rsync, and even via email. Currently there is no standard way 133 to verify the authenticity of a stand-alone zone. 135 This document introduces a new RR type that serves as a cryptographic 136 message digest of the data in a zone. It allows a receiver of the 137 zone to verify the zone's authenticity, especially when used in 138 combination with DNSSEC. This technique makes the message digest a 139 part of the zone itself, allowing verification the zone as a whole, 140 no matter how it is transmitted. Furthermore, the digest is based on 141 the wire format of zone data. Thus, it is independent of 142 presentation format, such as changes in whitespace, capitalization, 143 and comments. 145 DNSSEC provides three strong security guarantees relevant to this 146 protocol: 148 1. whether or not to expect DNSSEC records in the zone, 150 2. whether or not to expect a ZONEMD record in a signed zone, and 152 3. whether or not the ZONEMD record has been altered since it was 153 signed. 155 This specification is OPTIONAL to implement by both publishers and 156 consumers of zone data. 158 1.1. Motivation 160 The motivation for this protocol enhancement is the desire for the 161 ability to verify the authenticity of a stand-alone zone, regardless 162 of how it is transmitted. A consumer of zone data should be able to 163 verify that the data is as-published by the zone operator. 165 One approach to preventing data tampering and corruption is to secure 166 the distribution channel. The DNS has a number of features that can 167 already be used for channel security. Perhaps the most widely used 168 is DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared 169 secret keys and a message digest to protect individual query and 170 response messages. It is generally used to authenticate and validate 171 UPDATE [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages. 173 DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another 174 protocol extension designed to authenticate individual DNS 175 transactions. Whereas SIG records were originally designed to cover 176 specific RR types, SIG(0) is used to sign an entire DNS message. 177 Unlike TSIG, SIG(0) uses public key cryptography rather than shared 178 secrets. 180 The Transport Layer Security protocol suite is also designed to 181 provide channel security. One can easily imagine the distribution of 182 zones over HTTPS-enabled web servers, as well as DNS-over-HTTPS 183 [dns-over-https], and perhaps even a future version of DNS-over-TLS 184 ([RFC7858]). 186 Unfortunately, the protections provided by these channel security 187 techniques are (in practice) ephemeral and are not retained after the 188 data transfer is complete. They can ensure that the client receives 189 the data from the expected server, and that the data sent by the 190 server is not modified during transmission. However, they do not 191 guarantee that the server transmits the data as originally published, 192 and do not provide any methods to verify data that is read after 193 transmission is complete. For example, a name server loading saved 194 zone data upon restart cannot guarantee that the on-disk data has not 195 been modified. For these reasons, it is preferable to secure the 196 data itself. 198 Why not simply rely on DNSSEC, which provides certain data security 199 guarantees? Certainly for zones that are signed, a recipient could 200 validate all of the signed RRSets. Additionally, denial-of-existence 201 records can prove that RRSets have not been added or removed. 202 However, not all RRSets in a zone are signed. The design of DNSSEC 203 stipulates that delegations (non-apex NS records) are not signed, and 204 neither are any glue records. Thus, changes to delegation and glue 205 records cannot be detected by DNSSEC alone. Furthermore, zones that 206 employ NSEC3 with opt-out are susceptible to the removal or addition 207 of names between the signed nodes. Whereas DNSSEC is primarily 208 designed to protect consumers of DNS response messages, this protocol 209 is designed to protect consumers of zones. 211 There are existing tools and protocols that provide data security, 212 such as OpenPGP [RFC4880] and S/MIME [RFC3851]. In fact, the 213 internic.net site publishes PGP signatures along side the root zone 214 and other files available there. However, this is a detached 215 signature with no strong association to the corresponding zone file 216 other than its timestamp. Non-detached signatures are, of course, 217 possible, but these necessarily change the format of the file being 218 distributed. That is, a zone signed with OpenPGP or S/MIME no longer 219 looks like a DNS zone and could not directly be loaded into a name 220 server. Once loaded the signature data is lost, so it does not 221 survive further propagation. 223 It seems the desire for data security in DNS zones was envisioned as 224 far back as 1997. [RFC2065] is an obsoleted specification of the 225 first generation DNSSEC Security Extensions. It describes a zone 226 transfer signature, aka AXFR SIG, which is similar to the technique 227 proposed by this document. That is, it proposes ordering all 228 (signed) RRSets in a zone, hashing their contents, and then signing 229 the zone hash. The AXFR SIG is described only for use during zone 230 transfers. It did not postulate the need to validate zone data 231 distributed outside of the DNS. Furthermore, its successor, 232 [RFC2535], omits the AXFR SIG, while at the same time introducing an 233 IXFR SIG. 235 1.2. Design Overview 237 This document introduces a new Resource Record type designed to 238 convey a message digest of the content of a zone. The digest is 239 calculated at the time of zone publication. Ideally the zone is 240 signed with DNSSEC to guarantee that any modifications of the digest 241 can be detected. The procedures for digest calculation and DNSSEC 242 signing are similar (i.e., both require the same ordering of RRs) and 243 can be done in parallel. 245 The zone digest is designed to be used on zones that are relatively 246 stable and have infrequent updates. As currently specified, the 247 digest is re-calculated over the entire zone content each time. This 248 specification does not provide an efficient mechanism for incremental 249 updates of zone data. It does, however, reserve a field in the 250 ZONEMD record for future work to support incremental zone digest 251 algorithms (e.g. using Merkle trees). 253 It is expected that verification of a zone digest would be 254 implemented in name server software. That is, a name server can 255 verify the zone data it was given and refuse to serve a zone which 256 fails verification. For signed zones, the name server needs a trust 257 anchor to perform DNSSEC validation. For signed non-root zones, the 258 name server may need to send queries to validate a chain-of-trust. 259 Digest verification could also be performed externally. 261 1.3. Use Cases 263 1.3.1. Root Zone 265 The root zone [InterNIC] is one of the most widely distributed DNS 266 zone on the Internet, served by 930 separate instances [RootServers] 267 at the time of this writing. Additionally, many organizations 268 configure their own name servers to serve the root zone locally. 269 Reasons for doing so include privacy and reduced access time. 270 [RFC7706] describes one, but not the only, way to do this. As the 271 root zone spreads beyond its traditional deployment boundaries, the 272 need for verification of the completeness of the zone contents 273 becomes increasingly important. 275 1.3.2. Providers, Secondaries, and Anycast 277 Since its very early days, the developers of the DNS recognized the 278 importance of secondary name servers and service diversity. However, 279 they may not have anticipated the complexity of modern DNS service 280 provisioning which can include multiple third-party providers and 281 hundreds of anycast instances. Instead of a simple primary-to- 282 secondary zone distribution system, today it is possible to have 283 multiple levels, multiple parties, and multiple protocols involved in 284 the distribution of zone data. This complexity introduces new places 285 for problems to arise. The zone digest protects the integrity of 286 data that flows through such systems. 288 1.3.3. Response Policy Zones 290 DNS Response Policy Zones is "a method of expressing DNS response 291 policy information inside specially constructed DNS zones..." [RPZ]. 292 A number of companies provide RPZ feeds, which can be consumed by 293 name server and firewall products. Since these are zones, AXFR is 294 often, but not necessarily used for transmission. While RPZ zones 295 can certainly be signed with DNSSEC, the data is not queried 296 directly, and would not be subject to DNSSEC validation. 298 1.3.4. Centralized Zone Data Service 300 ICANN operates the Centralized Zone Data Service [CZDS], which is a 301 repository of top-level domain zone files. Users request access to 302 the system, and to individual zones, and are then able to download 303 zone data for certain uses. Adding a zone digest to these would 304 provide CZDS users with assurances that the data has not been 305 modified. Note that ZONEMD could be added to CZDS zone data 306 independently of the zone served by production name servers. 308 1.3.5. General Purpose Comparison Check 310 Since the zone digest does not depend on presentation format, it 311 could be used to compare multiple copies of a zone received from 312 different sources, or copies generated by different processes. 314 1.4. Requirements Language 316 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 317 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 318 "OPTIONAL" in this document are to be interpreted as described in BCP 319 14 [RFC2119] [RFC8174] when, and only when, they appear in all 320 capitals, as shown here. 322 2. The ZONEMD Resource Record 324 This section describes the ZONEMD Resource Record, including its 325 fields, wire format, and presentation format. The Type value for the 326 ZONEMD RR is 63. The ZONEMD RR is class independent. The RDATA of 327 the resource record consists of four fields: Serial, Digest Type, 328 Reserved, and Digest. 330 This specification utilizes ZONEMD RRs located at the zone apex. 331 Non-apex ZONEMD RRs are not forbidden, but have no meaning in this 332 specification. 334 A zone MAY contain multiple ZONEMD RRs to support algorithm agility 335 [RFC7696] and rollovers. Each ZONEMD RR MUST specify a unique Digest 336 Type. It is RECOMMENDED that a zone include only one ZONEMD RR, 337 unless the zone publisher is in the process of transitioning to a new 338 Digest Type. 340 2.1. ZONEMD RDATA Wire Format 342 The ZONEMD RDATA wire format is encoded as follows: 344 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 345 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 1 346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 347 | Serial | 348 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 349 | Digest Type | Reserved | | 350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 351 | Digest | 352 / / 353 / / 354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 356 2.1.1. The Serial Field 358 The Serial field is a 32-bit unsigned integer in network order. It 359 is equal to the serial number from the zone's SOA record ([RFC1035] 360 section 3.3.13) for which the message digest was generated. 362 The zone's serial number is included here in order to make DNS 363 response messages of type ZONEMD meaningful. Without the serial 364 number, a stand-alone ZONEMD digest has no association to any 365 particular instance of a zone. 367 2.1.2. The Digest Type Field 369 The Digest Type field is an 8-bit unsigned integer that identifies 370 the algorithm used to construct the digest. 372 At the time of this writing, SHA384, with value 1, is the only 373 standardized Digest Type defined for ZONEMD records. The Digest Type 374 registry is further described in Section 6. 376 Digest Type values 240-254 are allocated for Private Use as described 377 in [RFC8126]. 379 2.1.3. The Reserved Field 381 The Reserved field is an 8-bit unsigned integer, which is always set 382 to zero. This field is reserved for future work to support efficient 383 incremental updates. 385 2.1.4. The Digest Field 387 The Digest field is a variable-length sequence of octets containing 388 the message digest. The Digest field MUST NOT be empty. Section 3 389 describes how to calculate the digest for a zone. Section 4 390 describes how to use the digest to verify the contents of a zone. 392 2.2. ZONEMD Presentation Format 394 The presentation format of the RDATA portion is as follows: 396 The Serial field MUST be represented as an unsigned decimal integer. 398 The Digest Type field MUST be represented as an unsigned decimal 399 integer. 401 The Reserved field MUST be represented as an unsigned decimal integer 402 set to zero. 404 The Digest MUST be represented as a sequence of case-insensitive 405 hexadecimal digits. Whitespace is allowed within the hexadecimal 406 text. 408 2.3. ZONEMD Example 410 The following example shows a ZONEMD RR. 412 example.com. 86400 IN ZONEMD 2018031500 1 0 ( 413 FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE 414 7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE ) 416 3. Calculating the Digest 418 3.1. Canonical Format and Ordering 420 Calculation of the zone digest REQUIRES the RRs in a zone to be 421 processed in a consistent format and ordering. Correct ordering of 422 the zone depends on (1) ordering of owner names in the zone, (2) 423 ordering of RRSets with the same owner name, and (3) ordering of RRs 424 within an RRSet. 426 This specification adopts DNSSEC's canonical ordering for names 427 (Section 6.1 of [RFC4034]), and canonical ordering for RRs within an 428 RRSet (Section 6.3 of [RFC4034]). It also adopts DNSSEC's canonical 429 RR form (Section 6.2 of [RFC4034]). However, since DNSSEC does not 430 define a canonical ordering for RRSets having the same owner name, 431 that ordering is defined here. 433 3.1.1. Order of RRSets Having the Same Owner Name 435 For the purposes of calculating the zone digest, RRSets having the 436 same owner name MUST be numerically ordered, in ascending order, by 437 their numeric RR TYPE. 439 3.1.2. Duplicate RRs 441 As stated in Section 5 of [RFC2181], it is meaningless for a zone to 442 have multiple RRs with equal owner name, class, type, and RDATA. In 443 the interest of consistency and interoperability, such duplicate RRs 444 MUST NOT be included in the calculation of a zone digest. 446 3.2. Add ZONEMD Placeholder 448 In preparation for calculating the zone digest, any existing ZONEMD 449 records at the zone apex MUST first be deleted. 451 Prior to calculation of the digest, and prior to signing with DNSSEC, 452 a placeholder ZONEMD record MUST be added to the zone apex. This 453 serves two purposes: (1) it allows the digest to cover the Serial, 454 Digest Type, and Reserved field values, and (2) ensures that 455 appropriate denial-of-existence (NSEC, NSEC3) records are created if 456 the zone is signed with DNSSEC. 458 It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of 459 the SOA. 461 In the placeholder record, the Serial field MUST be set to the 462 current SOA Serial. The Digest Type field MUST be set to the value 463 for the chosen digest algorithm. The Reserved field MUST be set to 464 zero. The Digest field MUST be set to all zeroes and of length 465 appropriate for the chosen digest algorithm. 467 If multiple digests are to be published in the zone, e.g., during an 468 algorithm rollover, there MUST be one placeholder record for each 469 Digest Type. 471 3.3. Optionally Sign the Zone 473 Following addition of placeholder records, the zone MAY be signed 474 with DNSSEC. Note that when the digest calculation is complete, and 475 the ZONEMD record is updated, the signature(s) for the ZONEMD RRSet 476 MUST be recalculated and updated as well. Therefore, the signer is 477 not required to calculate a signature over the placeholder record at 478 this step in the process, but it is harmless to do so. 480 3.4. Calculate the Digest 482 The zone digest is calculated by concatenating the canonical on-the- 483 wire form (without name compression) of all RRs in the zone, in the 484 order described above, subject to the inclusion/exclusion rules 485 described below, and then applying the digest algorithm: 487 digest = digest_algorithm( RR(1) | RR(2) | RR(3) | ... ) 489 where "|" denotes concatenation, and 491 RR(i) = owner | type | class | TTL | RDATA length | RDATA 493 3.4.1. Inclusion/Exclusion Rules 495 When calculating the digest, the following inclusion/exclusion rules 496 apply: 498 o All records in the zone, including glue records, MUST be included. 500 o Occluded data ([RFC5936] Section 3.5) MUST be included. 502 o Duplicate RRs with equal owner, class, type, and RDATA MUST NOT be 503 included. 505 o The placeholder ZONEMD RR(s) MUST be included. 507 o If the zone is signed, DNSSEC RRs MUST be included, except: 509 o The RRSIG covering ZONEMD MUST NOT be included because the RRSIG 510 will be updated after all digests have been calculated. 512 3.5. Update ZONEMD RR 514 Once the zone digest has been calculated, its value is then copied to 515 the Digest field of the ZONEMD record. 517 If the zone is signed with DNSSEC, the appropriate RRSIG records 518 covering the ZONEMD RRSet MUST then be added or updated. Because the 519 ZONEMD placeholder was added prior to signing, the zone will already 520 have the appropriate denial-of-existence (NSEC, NSEC3) records. 522 Some implementations of incremental DNSSEC signing might update the 523 zone's serial number for each resigning. However, to preserve the 524 calculated digest, generation of the ZONEMD signature at this time 525 MUST NOT also result in a change of the SOA serial number. 527 4. Verifying Zone Message Digest 529 The recipient of a zone that has a message digest record can verify 530 the zone by calculating the digest as follows: 532 1. The verifier SHOULD first determine whether or not to expect 533 DNSSEC records in the zone. This can be done by examining 534 locally configured trust anchors, or querying for (and 535 validating) DS RRs in the parent zone. For zones that are 536 provably insecure, digest validation continues at step 4 below. 538 2. For zones that are provably secure, the existence of the apex 539 ZONEMD record MUST be verified. If the ZONEMD record provably 540 does not exist, digest verification cannot be done. If the 541 ZONEMD record does provably exist, but is not found in the zone, 542 digest verification MUST NOT be considered successful. 544 3. For zones that are provably secure, the SOA and ZONEMD RRSets 545 MUST have valid signatures, chaining up to a trust anchor. If 546 DNSSEC validation of the SOA or ZONEMD records fails, digest 547 verification MUST NOT be considered successful. 549 4. If the zone contains more than one apex ZONEMD RR, digest 550 verification MUST NOT be considered successful. 552 5. The SOA Serial field MUST exactly match the ZONEMD Serial field. 553 If the fields to not match, digest verification MUST NOT be 554 considered successful. 556 6. The ZONEMD Digest Type field MUST be checked. If the verifier 557 does not support the given digest type, it SHOULD report that 558 the zone digest could not be verified due to an unsupported 559 algorithm. 561 7. The Reserved field MUST be checked. If the Reserved field value 562 is not zero, verification MUST NOT be considered successful. 564 8. The received Digest Type and Digest values are copied to a 565 temporary location. 567 9. The ZONEMD RR's RDATA is reset to the placeholder values 568 described in Section 3.2. 570 10. The zone digest is computed over the zone data as described in 571 Section 3.4. 573 11. The calculated digest is compared to the received digest stored 574 in the temporary location. If the two digest values match, 575 verification is considered successful. Otherwise, verification 576 MUST NOT be considered successful. 578 12. The ZONEMD RR's RDATA is reset to the received Digest Type and 579 Digest stored in the temporary location. Thus, any downstream 580 clients can similarly verify the zone. 582 4.1. Verifying Multiple Digests 584 If multiple digests are present in the zone, e.g., during an 585 algorithm rollover, a match using any one of the recipient's 586 supported Digest Type algorithms is sufficient to verify the zone. 588 5. Scope of Experimentation 590 This memo is published as an Experimental RFC. The purpose of the 591 experimental period is to provide the community time to analyze and 592 evaluate the methods defined in this document, particularly with 593 regard to the wide variety of DNS zones in use on the Internet. 595 Additionally, the ZONEMD record defined in this document includes a 596 Reserved field in the form of an 8-bit integer. The authors have a 597 particular future use in mind for this field, namely to support 598 efficient digests in large, dynamic zones. We intend to conduct 599 future experiments using Merkle trees of varying depth. The choice 600 of tree depth can be encoded in this reserved field. We expect 601 values for tree depth to range from 0 to 10, requiring at most four 602 bits of this field. This leaves another four bits available for 603 other future uses, if absolutely necessary. 605 The duration of the experiment is expected to be no less than two 606 years from the publication of this document. If the experiment is 607 successful, it is expected that the findings of the experiment will 608 result in an updated document for Standards Track approval. 610 6. IANA Considerations 612 6.1. ZONEMD RRtype 614 This document defines a new DNS RR type, ZONEMD, whose value 63 has 615 been allocated by IANA from the "Resource Record (RR) TYPEs" 616 subregistry of the "Domain Name System (DNS) Parameters" registry: 618 Type: ZONEMD 620 Value: 63 622 Meaning: Message Digest Over Zone Data 623 Reference: This document 625 6.2. ZONEMD Digest Type 627 This document asks IANA to create a new "ZONEMD Digest Types" 628 registry with initial contents as follows: 630 +---------+-------------+-----------+-----------+ 631 | Value | Description | Status | Reference | 632 +---------+-------------+-----------+-----------+ 633 | 1 | SHA384 | Mandatory | [RFC6605] | 634 | 240-254 | Private Use | | [RFC8126] | 635 +---------+-------------+-----------+-----------+ 637 Table 1: ZONEMD Digest Types 639 7. Security Considerations 641 7.1. Attacks Against the Zone Digest 643 The zone digest allows the receiver to verify that the zone contents 644 haven't been modified since the zone was generated/published. 645 Verification is strongest when the zone is also signed with DNSSEC. 646 An attacker, whose goal is to modify zone content before it is used 647 by the victim, may consider a number of different approaches. 649 The attacker might perform a downgrade attack to an unsigned zone. 650 This is why Section 4 RECOMMENDS that the verifier determine whether 651 or not to expect DNSSEC signatures for the zone in step 1. 653 The attacker might perform a downgrade attack by removing the ZONEMD 654 record. This is why Section 4 REQUIRES that the verifier checks 655 DNSSEC denial-of-existence proofs in step 2. 657 The attacker might alter the Digest Type or Digest fields of the 658 ZONEMD record. Such modifications are detectable only with DNSSEC 659 validation. 661 7.2. Attacks Utilizing the Zone Digest 663 Nothing in this specification prevents clients from making, and 664 servers from responding to, ZONEMD queries. One might consider how 665 well ZONEMD responses could be used in a distributed denial-of- 666 service amplification attack. 668 The ZONEMD RR is moderately sized, much like the DS RR. A single 669 ZONEMD RR contributes approximately 40 to 65 octets to a DNS 670 response, for currently defined digest types. Certainly other query 671 types result in larger amplification effects (i.e., DNSKEY). 673 8. Privacy Considerations 675 This specification has no impacts on user privacy. 677 9. Acknowledgments 679 The authors wish to thank David Blacka, Scott Hollenbeck, and Rick 680 Wilhelm for providing feedback on early drafts of this document. 681 Additionally, they thank Joe Abley, Mark Andrews, Olafur Gudmundsson, 682 Paul Hoffman, Evan Hunt, Shumon Huque, Tatuya Jinmei, Burt Kaliski, 683 Shane Kerr, Matt Larson, John Levine, Ed Lewis, Matt Pounsett, Mukund 684 Sivaraman, Petr Spacek, Ondrej Sury, Florian Weimer, Tim Wicinksi, 685 Paul Wouters, and other members of the dnsop working group for their 686 input. 688 10. Implementation Status 690 10.1. Authors' Implementation 692 The authors have an open source implementation in C, using the ldns 693 library [ldns-zone-digest]. This implementation is able to perform 694 the following functions: 696 o Read an input zone and output a zone with the ZONEMD placeholder. 698 o Compute zone digest over signed zone and update the ZONEMD record. 700 o Re-compute DNSSEC signature over the ZONEMD record. 702 o Verify the zone digest from an input zone. 704 This implementation does not: 706 o Perform DNSSEC validation of the ZONEMD record during 707 verification. 709 10.2. Shane Kerr's Implementation 711 Shane Kerr wrote an implementation of this specification during the 712 IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in 713 Python and is able to perform the following functions: 715 o Read an input zone and a output zone with ZONEMD record. 717 o Verify the zone digest from an input zone. 719 o Output the ZONEMD record in its defined presentation format. 721 This implementation does not: 723 o Re-compute DNSSEC signature over the ZONEMD record. 725 o Perform DNSSEC validation of the ZONEMD record. 727 11. Change Log 729 RFC Editor: Please remove this section. 731 This section lists substantial changes to the document as it is being 732 worked on. 734 From -00 to -01: 736 o Removed requirement to sort by RR CLASS. 738 o Added Kumari and Hardaker as coauthors. 740 o Added Change Log section. 742 o Minor clarifications and grammatical edits. 744 From -01 to -02: 746 o Emphasize desire for data security over channel security. 748 o Expanded motivation into its own subsection. 750 o Removed discussion topic whether or not to include serial in 751 ZONEMD. 753 o Clarified that a zone's NS records always sort before the SOA 754 record. 756 o Clarified that all records in the zone must are digested, except 757 as specified in the exclusion rules. 759 o Added for discussion out-of-zone and occluded records. 761 o Clarified that update of ZONEMD signature must not cause a serial 762 number change. 764 o Added persons to acknowledgments. 766 From -02 to -03: 768 o Added recommendation to set ZONEMD TTL to SOA TTL. 770 o Clarified that digest input uses uncompressed names. 772 o Updated Implementations section. 774 o Changed intended status from Standards Track to Experimental and 775 added Scope of Experiment section. 777 o Updated Motivation, Introduction, and Design Overview sections in 778 response to working group discussion. 780 o Gave ZONEMD digest types their own status, separate from DS digest 781 types. Request IANA to create a registry. 783 o Added Reserved field for future work supporting dynamic updates. 785 o Be more rigorous about having just ONE ZONEMD record in the zone. 787 o Expanded use cases. 789 From -03 to -04: 791 o Added an appendix with example zones and digests. 793 o Clarified that only apex ZONEMD RRs shall be processed. 795 From -04 to -05: 797 o Made SHA384 the only supported ZONEMD digest type. 799 o Disassociated ZONEMD digest types from DS digest types. 801 o Updates to Introduction based on list feedback. 803 o Changed "zone file" to "zone" everywhere. 805 o Restored text about why ZONEMD has a Serial field. 807 o Clarified ordering of RRSets having same owner to be numerically 808 ascending. 810 o Clarified that all duplicate RRs (not just SOA) must be suppressed 811 in digest calculation. 813 o Clarified that the Reserved field must be set to zero and checked 814 for zero in verification. 816 o Clarified that occluded data must be included. 818 o Clarified procedure for verification, using temporary location for 819 received digest. 821 o Explained why Reserved field is 8-bits. 823 o IANA Considerations section now more specific. 825 o Added complex zone to examples. 827 o 829 From -05 to -06: 831 o RR type code 63 was assigned to ZONEMD by IANA. 833 From -06 to -07: 835 o Fixed mistakes in ZONEMD examples. 837 o Added private use Digest Type values 240-254. 839 o Clarified that Digest field must not be empty. 841 From -07 to draft-ietf-dnsop-dns-zone-digest-00: 843 o Adopted by dnsop. 845 o Clarified further that non-apex ZONEMD RRs have no meaning. 847 o Changed "provably [un]signed" to "provably [in]secure". 849 o Allow multiple ZONEMD RRs to support algorithm agility/rollovers. 851 o Describe verification when there are multiple ZONEMD RRs. 853 From -00 to -01: 855 o Simplified requirements around verifying multiple digests. Any 856 one match is sufficient. 858 o Updated implementation notes. 860 o Both implementations produce expected results on examples given in 861 this document. 863 12. References 865 12.1. Normative References 867 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 868 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 869 . 871 [RFC1035] Mockapetris, P., "Domain names - implementation and 872 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 873 November 1987, . 875 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 876 Requirement Levels", BCP 14, RFC 2119, 877 DOI 10.17487/RFC2119, March 1997, 878 . 880 [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS 881 Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, 882 . 884 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 885 Rose, "Resource Records for the DNS Security Extensions", 886 RFC 4034, DOI 10.17487/RFC4034, March 2005, 887 . 889 [RFC6605] Hoffman, P. and W. Wijngaards, "Elliptic Curve Digital 890 Signature Algorithm (DSA) for DNSSEC", RFC 6605, 891 DOI 10.17487/RFC6605, April 2012, 892 . 894 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 895 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 896 May 2017, . 898 12.2. Informative References 900 [CZDS] Internet Corporation for Assigned Names and Numbers, 901 "Centralized Zone Data Service", October 2018, 902 . 904 [dns-over-https] 905 Hoffman, P. and P. McManus, "DNS Queries over HTTPS 906 (DoH)", draft-ietf-doh-dns-over-https-12 (work in 907 progress), June 2018, . 910 [InterNIC] 911 ICANN, "InterNIC FTP site", May 2018, 912 . 914 [ldns-zone-digest] 915 Verisign, "Implementation of Message Digests for DNS Zones 916 using the ldns library", July 2018, 917 . 919 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 920 DOI 10.17487/RFC1995, August 1996, 921 . 923 [RFC2065] Eastlake 3rd, D. and C. Kaufman, "Domain Name System 924 Security Extensions", RFC 2065, DOI 10.17487/RFC2065, 925 January 1997, . 927 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 928 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 929 RFC 2136, DOI 10.17487/RFC2136, April 1997, 930 . 932 [RFC2535] Eastlake 3rd, D., "Domain Name System Security 933 Extensions", RFC 2535, DOI 10.17487/RFC2535, March 1999, 934 . 936 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 937 Wellington, "Secret Key Transaction Authentication for DNS 938 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 939 . 941 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 942 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 943 2000, . 945 [RFC3851] Ramsdell, B., Ed., "Secure/Multipurpose Internet Mail 946 Extensions (S/MIME) Version 3.1 Message Specification", 947 RFC 3851, DOI 10.17487/RFC3851, July 2004, 948 . 950 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 951 Thayer, "OpenPGP Message Format", RFC 4880, 952 DOI 10.17487/RFC4880, November 2007, 953 . 955 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 956 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 957 . 959 [RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm 960 Agility and Selecting Mandatory-to-Implement Algorithms", 961 BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015, 962 . 964 [RFC7706] Kumari, W. and P. Hoffman, "Decreasing Access Time to Root 965 Servers by Running One on Loopback", RFC 7706, 966 DOI 10.17487/RFC7706, November 2015, 967 . 969 [RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS 970 Terminology", RFC 7719, DOI 10.17487/RFC7719, December 971 2015, . 973 [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., 974 and P. Hoffman, "Specification for DNS over Transport 975 Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 976 2016, . 978 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 979 Writing an IANA Considerations Section in RFCs", BCP 26, 980 RFC 8126, DOI 10.17487/RFC8126, June 2017, 981 . 983 [RootServers] 984 Root Server Operators, "Root Server Technical Operations", 985 July 2018, . 987 [RPZ] Vixie, P. and V. Schryver, "DNS Response Policy Zones 988 (RPZ)", draft-vixie-dnsop-dns-rpz-00 (work in progress), 989 June 2018, . 992 [ZoneDigestHackathon] 993 Kerr, S., "Prototype implementation of ZONEMD for the IETF 994 102 hackathon in Python", July 2018, 995 . 997 Appendix A. Example Zones With Digests 999 This appendix contains example zones with accurate ZONEMD records. 1000 These can be used to verify an implementation of the zone digest 1001 protocol. 1003 A.1. Simple EXAMPLE Zone 1005 Here, the EXAMPLE zone contains an SOA record, NS and glue records, 1006 and a ZONEMD record. 1008 example. 86400 IN SOA ns1 admin 2018031900 ( 1009 1800 900 604800 86400 ) 1010 86400 IN NS ns1 1011 86400 IN NS ns2 1012 86400 IN ZONEMD 2018031900 1 0 ( 1013 379ec2587d4fff35 1014 0062b9385a641476 1015 6f9c028e8cf09d8a 1016 7965537a68a2f149 1017 4e1c151f8cf6be05 1018 5bef4f27e6a87b13 ) 1019 ns1 3600 IN A 127.0.0.1 1020 ns2 3600 IN AAAA ::1 1022 A.2. Complex EXAMPLE Zone 1024 Here, the EXAMPLE zone contains duplicate RRs, and an occluded RR, 1025 and one out-of-zone RR. 1027 example. 86400 IN SOA ns1 admin 2018031900 ( 1028 1800 900 604800 86400 ) 1029 86400 IN NS ns1 1030 86400 IN NS ns2 1031 86400 IN ZONEMD 2018031900 1 0 ( 1032 c36e77eafdb7f3f6 1033 dcfac8bca1121e17 1034 2a7b57db2c88409a 1035 5c3d9247ba72b759 1036 6c735c1a76fc817a 1037 ad5c834f5a4bce16 ) 1038 ns1 3600 IN A 127.0.0.1 1039 ns2 3600 IN AAAA ::1 1040 occluded.sub 7200 IN TXT "I'm occluded but must be digested" 1041 sub 7200 IN NS ns1 1042 duplicate 300 IN TXT "I must be digested just once" 1043 duplicate 300 IN TXT "I must be digested just once" 1044 foo.test. 555 IN TXT "out-of-zone data must be excluded" 1045 non-apex 900 IN ZONEMD 2018031900 1 0 ( 1046 616c6c6f77656420 1047 6275742069676e6f 1048 7265642e20616c6c 1049 6f77656420627574 1050 2069676e6f726564 1051 2e20616c6c6f7765 ) 1053 A.3. EXAMPLE Zone with multiple digests 1055 Here, the EXAMPLE zone contains multiple ZONEMD records. Since only 1056 one Digest Type is defined at this time (SHA384), this example 1057 utilizes additional ZONEMD records with Digest Type values in the 1058 private range (240-254). These additional private-range digests are 1059 not verifiable, but note that their other fields (Serial, Reserved, 1060 Digest Type) are included in the calculation of all ZONEMD digests. 1062 example. 86400 IN SOA ns1 admin 2018031900 ( 1063 1800 900 604800 86400 ) 1064 example. 86400 IN NS ns1.example. 1065 example. 86400 IN NS ns2.example. 1066 example. 86400 IN ZONEMD 2018031900 1 0 ( 1067 c0218e8eeb4f0275 1068 d54c0e5ce7791f4d 1069 23742b4756708d50 1070 d7121a11d434baa8 1071 f869ebbb071a4bbb 1072 0457c87870bc8cdd ) 1073 example. 86400 IN ZONEMD 2018031900 240 0 ( 1074 e2d523f654b9422a 1075 96c5a8f44607bbee ) 1076 example. 86400 IN ZONEMD 2018031900 241 0 ( 1077 5732dd91240611f8 1078 314adb6b4769bdd2 ) 1079 example. 86400 IN ZONEMD 2018031900 242 0 ( 1080 7c32e06779315c7d 1081 81ba8c72f5cf9116 1082 496b6395 ) 1083 example. 86400 IN ZONEMD 2018031900 243 0 ( 1084 183770af4a629f80 1085 2e674e305b8d0d11 1086 3dfe0837 ) 1087 example. 86400 IN ZONEMD 2018031900 244 0 ( 1088 e1846540e33a9e41 1089 89792d18d5d131f6 1090 05fc283e ) 1091 ns1.example. 3600 IN A 127.0.0.1 1092 ns2.example. 86400 IN TXT "This example has multiple digests" 1093 ns2.example. 3600 IN AAAA ::1 1095 A.4. The URI.ARPA Zone 1097 The URI.ARPA zone retrieved 2018-10-21. 1099 ; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr 1100 ; (2 servers found) 1101 ;; global options: +cmd 1102 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1103 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1104 uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 ( 1105 20181028142623 20181007205525 47155 uri.arpa. 1106 eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi 1107 /pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e 1108 HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= ) 1109 uri.arpa. 86400 IN RRSIG NS 8 2 86400 ( 1110 20181028172020 20181007175821 47155 uri.arpa. 1111 ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln 1112 4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF 1113 Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= ) 1114 uri.arpa. 600 IN RRSIG MX 8 2 600 ( 1115 20181028170556 20181007175821 47155 uri.arpa. 1116 e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t 1117 lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK 1118 A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= ) 1119 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1120 20181028152832 20181007175821 15796 uri.arpa. 1121 nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286 1122 XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V 1123 chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR 1124 6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B 1125 dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd 1126 uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk 1127 5R0A1w== ) 1128 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1129 20181028152832 20181007175821 55480 uri.arpa. 1130 lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X 1131 nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV 1132 63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj 1133 2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75 1134 WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R 1135 PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA 1136 1HeBfw== ) 1137 uri.arpa. 3600 IN RRSIG SOA 8 2 3600 ( 1138 20181029114753 20181008222815 47155 uri.arpa. 1139 qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2 1140 Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu 1141 9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= ) 1142 uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA ( 1143 MX RRSIG NSEC DNSKEY ) 1144 uri.arpa. 86400 IN NS a.iana-servers.net. 1145 uri.arpa. 86400 IN NS b.iana-servers.net. 1146 uri.arpa. 86400 IN NS c.iana-servers.net. 1147 uri.arpa. 86400 IN NS ns2.lacnic.net. 1148 uri.arpa. 86400 IN NS sec3.apnic.net. 1149 uri.arpa. 600 IN MX 10 pechora.icann.org. 1150 uri.arpa. 3600 IN DNSKEY 256 3 8 ( 1151 AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK 1152 uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL 1153 Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx 1154 SdJjlH0B ) 1155 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1156 AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY 1157 cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc 1158 3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/ 1159 Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9 1160 iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5 1161 ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt 1162 l3wpbp+Wpm8= ) 1163 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1164 AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR 1165 wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD 1166 FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG 1167 mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU 1168 7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3 1169 e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0 1170 xmJVvNQlwdE= ) 1171 ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1172 20181028080856 20181007175821 47155 uri.arpa. 1173 HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9 1174 jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP 1175 Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= ) 1176 ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1177 20181028103644 20181007205525 47155 uri.arpa. 1178 WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0 1179 9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5 1180 YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= ) 1181 ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR ( 1182 RRSIG NSEC ) 1183 ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1184 "!^ftp://([^:/?#]*).*$!\\1!i" . ) 1185 http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1186 20181029010647 20181007175821 47155 uri.arpa. 1187 U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE 1188 H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+ 1189 ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= ) 1190 http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1191 20181029011815 20181007205525 47155 uri.arpa. 1192 T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F 1193 Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0 1194 RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= ) 1195 http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR ( 1196 RRSIG NSEC ) 1197 http.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1198 "!^http://([^:/?#]*).*$!\\1!i" . ) 1199 mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1200 20181028110727 20181007175821 47155 uri.arpa. 1201 GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/ 1202 IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl 1203 fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= ) 1204 mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1205 20181028141825 20181007205525 47155 uri.arpa. 1207 MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF 1208 j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg 1209 916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= ) 1210 mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR ( 1211 RRSIG NSEC ) 1212 mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1213 "!^mailto:(.*)@(.*)$!\\2!i" . ) 1214 urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1215 20181028123243 20181007175821 47155 uri.arpa. 1216 Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe 1217 UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9 1218 DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= ) 1219 urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1220 20181029071816 20181007205525 47155 uri.arpa. 1221 ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS 1222 D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW 1223 BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= ) 1224 urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG ( 1225 NSEC ) 1226 urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1227 "/urn:([^:]+)/\\1/i" . ) 1228 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1229 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1230 ;; Query time: 66 msec 1231 ;; SERVER: 192.0.32.132#53(192.0.32.132) 1232 ;; WHEN: Sun Oct 21 20:39:28 UTC 2018 1233 ;; XFR size: 34 records (messages 1, bytes 3941) 1234 uri.arpa. 3600 IN ZONEMD 2018100702 1 0 ( 1235 e4de6ed36e5d95706756932fae3ecbc6aeb76e16ce486a5553c7e4 1236 c9974d03323e7cd39ccc5e70e797179633f4007bad ) 1238 A.5. The ROOT-SERVERS.NET Zone 1240 The ROOT-SERVERS.NET zone retreived 2018-10-21. 1242 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1243 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1244 root-servers.net. 3600000 IN NS a.root-servers.net. 1245 root-servers.net. 3600000 IN NS b.root-servers.net. 1246 root-servers.net. 3600000 IN NS c.root-servers.net. 1247 root-servers.net. 3600000 IN NS d.root-servers.net. 1248 root-servers.net. 3600000 IN NS e.root-servers.net. 1249 root-servers.net. 3600000 IN NS f.root-servers.net. 1250 root-servers.net. 3600000 IN NS g.root-servers.net. 1251 root-servers.net. 3600000 IN NS h.root-servers.net. 1252 root-servers.net. 3600000 IN NS i.root-servers.net. 1253 root-servers.net. 3600000 IN NS j.root-servers.net. 1254 root-servers.net. 3600000 IN NS k.root-servers.net. 1255 root-servers.net. 3600000 IN NS l.root-servers.net. 1256 root-servers.net. 3600000 IN NS m.root-servers.net. 1257 a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30 1258 a.root-servers.net. 3600000 IN A 198.41.0.4 1259 b.root-servers.net. 3600000 IN MX 20 mail.isi.edu. 1260 b.root-servers.net. 3600000 IN AAAA 2001:500:200::b 1261 b.root-servers.net. 3600000 IN A 199.9.14.201 1262 c.root-servers.net. 3600000 IN AAAA 2001:500:2::c 1263 c.root-servers.net. 3600000 IN A 192.33.4.12 1264 d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d 1265 d.root-servers.net. 3600000 IN A 199.7.91.13 1266 e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e 1267 e.root-servers.net. 3600000 IN A 192.203.230.10 1268 f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f 1269 f.root-servers.net. 3600000 IN A 192.5.5.241 1270 g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d 1271 g.root-servers.net. 3600000 IN A 192.112.36.4 1272 h.root-servers.net. 3600000 IN AAAA 2001:500:1::53 1273 h.root-servers.net. 3600000 IN A 198.97.190.53 1274 i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org. 1275 i.root-servers.net. 3600000 IN AAAA 2001:7fe::53 1276 i.root-servers.net. 3600000 IN A 192.36.148.17 1277 j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30 1278 j.root-servers.net. 3600000 IN A 192.58.128.30 1279 k.root-servers.net. 3600000 IN AAAA 2001:7fd::1 1280 k.root-servers.net. 3600000 IN A 193.0.14.129 1281 l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42 1282 l.root-servers.net. 3600000 IN A 199.7.83.42 1283 m.root-servers.net. 3600000 IN AAAA 2001:dc3::35 1284 m.root-servers.net. 3600000 IN A 202.12.27.33 1285 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1286 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1287 root-servers.net. 3600000 IN ZONEMD 2018091100 1 0 ( 1288 0c1839d86088062868c1ed79aed6a301dc7b08b02ba2f67cbc62edd4a0 1289 291f4132b8840da47ddab4401cc9088d04a14a ) 1291 Authors' Addresses 1293 Duane Wessels 1294 Verisign 1295 12061 Bluemont Way 1296 Reston, VA 20190 1298 Phone: +1 703 948-3200 1299 Email: dwessels@verisign.com 1300 URI: http://verisign.com 1302 Piet Barber 1303 Verisign 1304 12061 Bluemont Way 1305 Reston, VA 20190 1307 Phone: +1 703 948-3200 1308 Email: pbarber@verisign.com 1309 URI: http://verisign.com 1311 Matt Weinberg 1312 Verisign 1313 12061 Bluemont Way 1314 Reston, VA 20190 1316 Phone: +1 703 948-3200 1317 Email: mweinberg@verisign.com 1318 URI: http://verisign.com 1320 Warren Kumari 1321 Google 1322 1600 Amphitheatre Parkway 1323 Mountain View, CA 94043 1325 Email: warren@kumari.net 1327 Wes Hardaker 1328 USC/ISI 1329 P.O. Box 382 1330 Davis, CA 95617 1332 Email: ietf@hardakers.net