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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: May 11, 2019 Verisign 6 W. Kumari 7 Google 8 W. Hardaker 9 USC/ISI 10 November 7, 2018 12 Message Digest for DNS Zones 13 draft-wessels-dns-zone-digest-05 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 May 11, 2019. 53 Copyright Notice 55 Copyright (c) 2018 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 . . . . . . . . . . . . . . . . . . 8 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 . . . . . 9 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 . . . . . . . . . . . . . . . . . . 10 95 3.4.1. Inclusion/Exclusion Rules . . . . . . . . . . . . . . 11 97 3.5. Update ZONEMD RR . . . . . . . . . . . . . . . . . . . . 11 98 4. Verifying Zone Message Digest . . . . . . . . . . . . . . . . 11 99 5. Scope of Experimentation . . . . . . . . . . . . . . . . . . 13 100 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 101 6.1. ZONEMD RRtype . . . . . . . . . . . . . . . . . . . . . . 13 102 6.2. ZONEMD Digest Type . . . . . . . . . . . . . . . . . . . 14 103 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 104 7.1. Attacks Against the Zone Digest . . . . . . . . . . . . . 14 105 7.2. Attacks Utilizing the Zone Digest . . . . . . . . . . . . 14 106 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 15 107 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 108 10. Implementation Status . . . . . . . . . . . . . . . . . . . . 15 109 10.1. Authors' Implementation . . . . . . . . . . . . . . . . 15 110 10.2. Shane Kerr's Implementation . . . . . . . . . . . . . . 15 111 11. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 16 112 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 113 12.1. Normative References . . . . . . . . . . . . . . . . . . 18 114 12.2. Informative References . . . . . . . . . . . . . . . . . 19 115 Appendix A. Example Zones With Digests . . . . . . . . . . . . . 21 116 A.1. Simple EXAMPLE Zone . . . . . . . . . . . . . . . . . . . 21 117 A.2. Complex EXAMPLE Zone . . . . . . . . . . . . . . . . . . 21 118 A.3. The URI.ARPA Zone . . . . . . . . . . . . . . . . . . . . 22 119 A.4. The ROOT-SERVERS.NET Zone . . . . . . . . . . . . . . . . 25 120 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 122 1. Introduction 124 In the DNS, a zone is the collection of authoritative resource 125 records (RRs) sharing a common origin ([RFC7719]). Zones are often 126 stored as files on disk in the so-called master file format 127 [RFC1034]. Zones are generally distributed among name servers using 128 the AXFR [RFC5936], and IXFR [RFC1995] protocols. Zone files can 129 also be distributed outside of the DNS, with such protocols as FTP, 130 HTTP, rsync, and even via email. Currently there is no standard way 131 to verify the authenticity of a stand-alone zone. 133 This document introduces a new RR type that serves as a cryptographic 134 message digest of the data in a zone. It allows a receiver of the 135 zone to verify the zone's authenticity, especially when used in 136 combination with DNSSEC. This technique makes the message digest a 137 part of the zone itself, allowing verification the zone as a whole, 138 no matter how it is transmitted. Furthermore, the digest is based on 139 the wire format of zone data. Thus, it is independent of 140 presentation format, such as changes in whitespace, capitalization, 141 and comments. 143 DNSSEC provides three strong security guarantees relevant to this 144 protocol: 146 1. whether or not to expect DNSSEC records in the zone, 148 2. whether or not to expect a ZONEMD record in a signed zone, and 150 3. whether or not the ZONEMD record has been altered since it was 151 signed. 153 This specification is OPTIONAL to implement by both publishers and 154 consumers of zone data. 156 1.1. Motivation 158 The motivation for this protocol enhancement is the desire for the 159 ability to verify the authenticity of a stand-alone zone, regardless 160 of how it is transmitted. A consumer of zone data should be able to 161 verify that the data is as-published by the zone operator. 163 One approach to preventing data tampering and corruption is to secure 164 the distribution channel. The DNS has a number of features that can 165 already be used for channel security. Perhaps the most widely used 166 is DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared 167 secret keys and a message digest to protect individual query and 168 response messages. It is generally used to authenticate and validate 169 UPDATE [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages. 171 DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another 172 protocol extension designed to authenticate individual DNS 173 transactions. Whereas SIG records were originally designed to cover 174 specific RR types, SIG(0) is used to sign an entire DNS message. 175 Unlike TSIG, SIG(0) uses public key cryptography rather than shared 176 secrets. 178 The Transport Layer Security protocol suite is also designed to 179 provide channel security. One can easily imagine the distribution of 180 zones over HTTPS-enabled web servers, as well as DNS-over-HTTPS 181 [dns-over-https], and perhaps even a future version of DNS-over-TLS 182 ([RFC7858]). 184 Unfortunately, the protections provided by these channel security 185 techniques are (in practice) ephemeral and are not retained after the 186 data transfer is complete. They can ensure that the client receives 187 the data from the expected server, and that the data sent by the 188 server is not modified during transmission. However, they do not 189 guarantee that the server transmits the data as originally published, 190 and do not provide any methods to verify data that is read after 191 transmission is complete. For example, a name server loading saved 192 zone data upon restart cannot guarantee that the on-disk data has not 193 been modified. For these reasons, it is preferable to secure the 194 data itself. 196 Why not simply rely on DNSSEC, which provides certain data security 197 guarantees? Certainly for zones that are signed, a recipient could 198 validate all of the signed RRSets. Additionally, denial-of-existence 199 records can prove that RRSets have not been added or removed. 200 However, not all RRSets in a zone are signed. The design of DNSSEC 201 stipulates that delegations (non-apex NS records) are not signed, and 202 neither are any glue records. Thus, changes to delegation and glue 203 records cannot be detected by DNSSEC alone. Furthermore, zones that 204 employ NSEC3 with opt-out are susceptible to the removal or addition 205 of names between the signed nodes. Whereas DNSSEC is primarily 206 designed to protect consumers of DNS response messages, this protocol 207 is designed to protect consumers of zones. 209 There are existing tools and protocols that provide data security, 210 such as OpenPGP [RFC4880] and S/MIME [RFC3851]. In fact, the 211 internic.net site publishes PGP signatures along side the root zone 212 and other files available there. However, this is a detached 213 signature with no strong association to the corresponding zone file 214 other than its timestamp. Non-detached signatures are, of course, 215 possible, but these necessarily change the format of the file being 216 distributed. That is, a zone signed with OpenPGP or S/MIME no longer 217 looks like a DNS zone and could not directly be loaded into a name 218 server. Once loaded the signature data is lost, so it does not 219 survive further propagation. 221 It seems the desire for data security in DNS zones was envisioned as 222 far back as 1997. [RFC2065] is an obsoleted specification of the 223 first generation DNSSEC Security Extensions. It describes a zone 224 transfer signature, aka AXFR SIG, which is similar to the technique 225 proposed by this document. That is, it proposes ordering all 226 (signed) RRSets in a zone, hashing their contents, and then signing 227 the zone hash. The AXFR SIG is described only for use during zone 228 transfers. It did not postulate the need to validate zone data 229 distributed outside of the DNS. Furthermore, its successor, 230 [RFC2535], omits the AXFR SIG, while at the same time introducing an 231 IXFR SIG. 233 1.2. Design Overview 235 This document introduces a new Resource Record type designed to 236 convey a message digest of the content of a zone. The digest is 237 calculated at the time of zone publication. Ideally the zone is 238 signed with DNSSEC to guarantee that any modifications of the digest 239 can be detected. The procedures for digest calculation and DNSSEC 240 signing are similar (i.e., both require the same ordering of RRs) and 241 can be done in parallel. 243 The zone digest is designed to be used on zones that are relatively 244 stable and have infrequent updates. As currently specified, the 245 digest is re-calculated over the entire zone content each time. This 246 specification does not provide an efficient mechanism for incremental 247 updates of zone data. It does, however, reserve a field in the 248 ZONEMD record for future work to support incremental zone digest 249 algorithms (e.g. using Merkle trees). 251 It is expected that verification of a zone digest would be 252 implemented in name server software. That is, a name server can 253 verify the zone data it was given and refuse to serve a zone which 254 fails verification. For signed zones, the name server needs a trust 255 anchor to perform DNSSEC validation. For signed non-root zones, the 256 name server may need to send queries to validate a chain-of-trust. 257 Digest verification could also be performed externally. 259 1.3. Use Cases 261 1.3.1. Root Zone 263 The root zone [InterNIC] is one of the most widely distributed DNS 264 zone on the Internet, served by 930 separate instances [RootServers] 265 at the time of this writing. Additionally, many organizations 266 configure their own name servers to serve the root zone locally. 267 Reasons for doing so include privacy and reduced access time. 268 [RFC7706] describes one, but not the only, way to do this. As the 269 root zone spreads beyond its traditional deployment boundaries, the 270 need for verification of the completeness of the zone contents 271 becomes increasingly important. 273 1.3.2. Providers, Secondaries, and Anycast 275 Since its very early days, the developers of the DNS recognized the 276 importance of secondary name servers and service diversity. However, 277 they may not have anticipated the complexity of modern DNS service 278 provisioning which can include multiple third-party providers and 279 hundreds of anycast instances. Instead of a simple primary-to- 280 secondary zone distribution system, today it is possible to have 281 multiple levels, multiple parties, and multiple protocols involved in 282 the distribution of zone data. This complexity introduces new places 283 for problems to arise. The zone digest protects the integrity of 284 data that flows through such systems. 286 1.3.3. Response Policy Zones 288 DNS Response Policy Zones is "a method of expressing DNS response 289 policy information inside specially constructed DNS zones..." [RPZ]. 290 A number of companies provide RPZ feeds, which can be consumed by 291 name server and firewall products. Since these are zones, AXFR is 292 often, but not necessarily used for transmission. While RPZ zones 293 can certainly be signed with DNSSEC, the data is not queried 294 directly, and would not be subject to DNSSEC validation. 296 1.3.4. Centralized Zone Data Service 298 ICANN operates the Centralized Zone Data Service [CZDS], which is a 299 repository of top-level domain zone files. Users request access to 300 the system, and to individual zones, and are then able to download 301 zone data for certain uses. Adding a zone digest to these would 302 provide CZDS users with assurances that the data has not been 303 modified. Note that ZONEMD could be added to CZDS zone data 304 independently of the zone served by production name servers. 306 1.3.5. General Purpose Comparison Check 308 Since the zone digest does not depend on presentation format, it 309 could be used to compare multiple copies of a zone received from 310 different sources, or copies generated by different processes. 312 1.4. Requirements Language 314 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 315 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 316 "OPTIONAL" in this document are to be interpreted as described in BCP 317 14 [RFC2119] [RFC8174] when, and only when, they appear in all 318 capitals, as shown here. 320 2. The ZONEMD Resource Record 322 This section describes the ZONEMD Resource Record, including its 323 fields, wire format, and presentation format. The Type value for the 324 ZONEMD RR is TBD. The ZONEMD RR is class independent. The RDATA of 325 the resource record consists of four fields: Serial, Digest Type, 326 Reserved, and Digest. 328 FOR DISCUSSION: This document is currently written as though a zone 329 MUST NOT contain more than one ZONEMD RR. Having exactly one ZONEMD 330 record per zone simplifies this protocol and eliminates confusion 331 around downgrade attacks, at the expense of algorithm agility. 333 2.1. ZONEMD RDATA Wire Format 335 The ZONEMD RDATA wire format is encoded as follows: 337 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 338 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 1 339 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 340 | Serial | 341 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 | Digest Type | Reserved | | 343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 344 | Digest | 345 / / 346 / / 347 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 349 2.1.1. The Serial Field 351 The Serial field is a 32-bit unsigned integer in network order. It 352 is equal to the serial number from the zone's SOA record ([RFC1035] 353 section 3.3.13) for which the message digest was generated. 355 The zone's serial number is included here in order to make DNS 356 response messages of type ZONEMD meaningful. Without the serial 357 number, a stand-alone ZONEMD digest has no association to any 358 particular instance of a zone. 360 2.1.2. The Digest Type Field 362 The Digest Type field is an 8-bit unsigned integer that identifies 363 the algorithm used to construct the digest. 365 At the time of this writing, SHA384, with value 1, is the only Digest 366 Type defined for ZONEMD records. The Digest Type registry is further 367 described in Section 6. 369 2.1.3. The Reserved Field 371 The Reserved field is an 8-bit unsigned integer, which is always set 372 to zero. This field is reserved for future work to support efficient 373 incremental updates. 375 2.1.4. The Digest Field 377 The Digest field is a variable-length sequence of octets containing 378 the message digest. Section 3 describes how to calculate the digest 379 for a zone. Section 4 describes how to use the digest to verify the 380 contents of a zone. 382 2.2. ZONEMD Presentation Format 384 The presentation format of the RDATA portion is as follows: 386 The Serial field MUST be represented as an unsigned decimal integer. 388 The Digest Type field MUST be represented as an unsigned decimal 389 integer. 391 The Reserved field MUST be represented as an unsigned decimal integer 392 set to zero. 394 The Digest MUST be represented as a sequence of case-insensitive 395 hexadecimal digits. Whitespace is allowed within the hexadecimal 396 text. 398 2.3. ZONEMD Example 400 The following example shows a ZONEMD RR. 402 example.com. 86400 IN ZONEMD 2018031500 4 0 ( 403 FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE 404 7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE ) 406 3. Calculating the Digest 408 3.1. Canonical Format and Ordering 410 Calculation of the zone digest REQUIRES the RRs in a zone to be 411 processed in a consistent format and ordering. Correct ordering of 412 the zone depends on (1) ordering of owner names in the zone, (2) 413 ordering of RRSets with the same owner name, and (3) ordering of RRs 414 within an RRSet. 416 This specification adopts DNSSEC's canonical ordering for names 417 (Section 6.1 of [RFC4034]), and canonical ordering for RRs within an 418 RRSet (Section 6.3 of [RFC4034]). It also adopts DNSSEC's canonical 419 RR form (Section 6.2 of [RFC4034]). However, since DNSSEC does not 420 define a canonical ordering for RRSets having the same owner name, 421 that ordering is defined here. 423 3.1.1. Order of RRSets Having the Same Owner Name 425 For the purposes of calculating the zone digest, RRSets having the 426 same owner name MUST be numerically ordered, in ascending order, by 427 their numeric RR TYPE. 429 3.1.2. Duplicate RRs 431 As stated in Section 5 of [RFC2181], it is meaningless for a zone to 432 have multiple RRs with equal owner name, class, type, and RDATA. In 433 the interest of consistency and interoperability, such duplicate RRs 434 MUST NOT be included in the calculation of a zone digest. 436 3.2. Add ZONEMD Placeholder 438 In preparation for calculating the zone digest, any existing ZONEMD 439 record at the zone apex MUST first be deleted. 441 FOR DISCUSSION: Should non-apex ZONEMD records be allowed in a zone? 442 Or forbidden? 444 Prior to calculation of the digest, and prior to signing with DNSSEC, 445 a placeholder ZONEMD record MUST be added to the zone apex. This 446 serves two purposes: (1) it allows the digest to cover the Serial, 447 Digest Type, and Reserved field values, and (2) ensures that 448 appropriate denial-of-existence (NSEC, NSEC3) records are created if 449 the zone is signed with DNSSEC. 451 It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of 452 the SOA. 454 In the placeholder record, the Serial field MUST be set to the 455 current SOA Serial. The Digest Type field MUST be set to the value 456 for the chosen digest algorithm. The Reserved field MUST be set to 457 zero. The Digest field MUST be set to all zeroes and of length 458 appropriate for the chosen digest algorithm. 460 3.3. Optionally Sign the Zone 462 Following addition of the placeholder record, the zone MAY be signed 463 with DNSSEC. Note that when the digest calculation is complete, and 464 the ZONEMD record is updated, the signature(s) for that record MUST 465 be recalculated and updated as well. Therefore, the signer is not 466 required to calculate a signature over the placeholder record at this 467 step in the process, but it is harmless to do so. 469 3.4. Calculate the Digest 471 The zone digest is calculated by concatenating the canonical on-the- 472 wire form (without name compression) of all RRs in the zone, in the 473 order described above, subject to the inclusion/exclusion rules 474 described below, and then applying the digest algorithm: 476 digest = digest_algorithm( RR(1) | RR(2) | RR(3) | ... ) 478 where "|" denotes concatenation, and 480 RR(i) = owner | type | class | TTL | RDATA length | RDATA 482 3.4.1. Inclusion/Exclusion Rules 484 When calculating the digest, the following inclusion/exclusion rules 485 apply: 487 o All records in the zone, including glue records, MUST be included. 489 o Occluded data ([RFC5936] Section 3.5) MUST be included. 491 o Duplicate RRs with equal owner, class, type, and RDATA MUST NOT be 492 included. 494 o The placeholder ZONEMD RR MUST be included. 496 o If the zone is signed, DNSSEC RRs MUST be included, except: 498 o The RRSIG covering ZONEMD MUST NOT be included. 500 3.5. Update ZONEMD RR 502 Once the zone digest has been calculated, its value is then copied to 503 the Digest field of the ZONEMD record. 505 If the zone is signed with DNSSEC, the appropriate RRSIG records 506 covering the ZONEMD record MUST then be added or updated. Because 507 the ZONEMD placeholder was added prior to signing, the zone will 508 already have the appropriate denial-of-existence (NSEC, NSEC3) 509 records. 511 Some implementations of incremental DNSSEC signing might update the 512 zone's serial number for each resigning. However, to preserve the 513 calculated digest, generation of the ZONEMD signature at this time 514 MUST NOT also result in a change of the SOA serial number. 516 4. Verifying Zone Message Digest 518 The recipient of a zone that has a message digest record can verify 519 the zone by calculating the digest as follows: 521 1. The verifier SHOULD first determine whether or not to expect 522 DNSSEC records in the zone. This can be done by examining 523 locally configured trust anchors, or querying for (and 524 validating) DS RRs in the parent zone. For zones that are 525 provably unsigned, digest validation continues at step 4 below. 527 2. For zones that are provably signed, the existence of the apex 528 ZONEMD record MUST be verified. If the ZONEMD record provably 529 does not exist, digest verification cannot be done. If the 530 ZONEMD record does provably exist, but is not found in the zone, 531 digest verification MUST NOT be considered successful. 533 3. For zones that are provably signed, the SOA RR and ZONEMD RR 534 MUST have valid signatures, chaining up to a trust anchor. If 535 DNSSEC validation of the SOA or ZONEMD records fails, digest 536 verification MUST NOT be considered successful. 538 4. If the zone contains more than one apex ZONEMD RR, digest 539 verification MUST NOT be considered successful. 541 5. The SOA Serial field MUST exactly match the ZONEMD Serial field. 542 If the fields to not match, digest verification MUST NOT be 543 considered successful. 545 6. The ZONEMD Digest Type field MUST be checked. If the verifier 546 does not support the given digest type, it SHOULD report that 547 the zone digest could not be verified due to an unsupported 548 algorithm. 550 7. The Reserved field MUST be checked. If the Reserved field value 551 is not zero, verification MUST NOT be considered successful. 553 8. The received Digest Type and Digest values are copied to a 554 temporary location. 556 9. The ZONEMD RR's RDATA is reset to the placeholder values 557 described in Section 3.2. 559 10. The zone digest is computed over the zone data as described in 560 Section 3.4. 562 11. The calculated digest is compared to the received digest stored 563 in the temporary location. If the two digest values match, 564 verification is considered successful. Otherwise, verification 565 MUST NOT be considered successful. 567 12. The ZONEMD RR's RDATA is reset to the received Digest Type and 568 Digest stored in the temporary location. Thus, any downstream 569 clients can similarly verify the zone. 571 5. Scope of Experimentation 573 This memo is published as an Experimental RFC. The purpose of the 574 experimental period is to provide the community time to analyze and 575 evaluate to the methods defined in this document, particularly with 576 regard to the wide variety of DNS zones in use on the Internet. 578 Additionally, the ZONEMD record defined in this document includes a 579 Reserved field in the form of an 8-bit integer. The authors have a 580 particular future use in mind for this field, namely to support 581 efficient digests in large, dynamic zones. We intend to conduct 582 future experiments using Merkle trees of varying depth. The choice 583 of tree depth can be encoded in this reserved field. We expect 584 values for tree depth to range from 0 to 10, requiring at most four 585 bits of this field. This leaves another four bits available for 586 other future uses, if absolutely necessary. 588 FOR DISCUSSION: The authors are willing to remove the Reserved field 589 from this specification if the working group would prefer it. It 590 would mean, however, that a future version of this protocol designed 591 to efficiently support large, dynamic zones would most likely require 592 a new RR type. 594 The duration of the experiment is expected to be no less than two 595 years from the publication of this document. If the experiment is 596 successful, it is expected that the findings of the experiment will 597 result in an updated document for Standards Track approval. 599 6. IANA Considerations 601 6.1. ZONEMD RRtype 603 This document defines a new DNS RR type, ZONEMD, whose value TBD has 604 been allocated by IANA from the "Resource Record (RR) TYPEs" 605 subregistry of the "Domain Name System (DNS) Parameters" registry: 607 Type: ZONEMD 609 Value: TBD 611 Meaning: Message Digest Over Zone Data 613 Reference: This document 615 6.2. ZONEMD Digest Type 617 This document asks IANA to create a new "ZONEMD Digest Types" 618 registry with initial contents as follows: 620 +-------+-------------+-----------+-----------+ 621 | Value | Description | Status | Reference | 622 +-------+-------------+-----------+-----------+ 623 | 1 | SHA384 | Mandatory | [RFC6605] | 624 +-------+-------------+-----------+-----------+ 626 Table 1: ZONEMD Digest Types 628 7. Security Considerations 630 7.1. Attacks Against the Zone Digest 632 The zone digest allows the receiver to verify that the zone contents 633 haven't been modified since the zone was generated/published. 634 Verification is strongest when the zone is also signed with DNSSEC. 635 An attacker, whose goal is to modify zone content before it is used 636 by the victim, may consider a number of different approaches. 638 The attacker might perform a downgrade attack to an unsigned zone. 639 This is why Section 4 RECOMMENDS that the verifier determine whether 640 or not to expect DNSSEC signatures for the zone in step 1. 642 The attacker might perform a downgrade attack by removing the ZONEMD 643 record. This is why Section 4 REQUIRES that the verifier checks 644 DNSSEC denial-of-existence proofs in step 2. 646 The attacker might alter the Digest Type or Digest fields of the 647 ZONEMD record. Such modifications are detectable only with DNSSEC 648 validation. 650 7.2. Attacks Utilizing the Zone Digest 652 Nothing in this specification prevents clients from making, and 653 servers from responding to, ZONEMD queries. One might consider how 654 well ZONEMD responses could be used in a distributed denial-of- 655 service amplification attack. 657 The ZONEMD RR is moderately sized, much like the DS RR. A single 658 ZONEMD RR contributes approximately 40 to 65 octets to a DNS 659 response, for currently defined digest types. Certainly other query 660 types result in larger amplification effects (i.e., DNSKEY). 662 8. Privacy Considerations 664 This specification has no impacts on user privacy. 666 9. Acknowledgments 668 The authors wish to thank David Blacka, Scott Hollenbeck, and Rick 669 Wilhelm for providing feedback on early drafts of this document. 670 Additionally, they thank Joe Abley, Mark Andrews, Olafur Gudmundsson, 671 Paul Hoffman, Evan Hunt, Shumon Huque, Tatuya Jinmei, Burt Kaliski, 672 Shane Kerr, Matt Larson, John Levine, Ed Lewis, Mukund Sivaraman, 673 Petr Spacek, Ondrej Sury, Florian Weimer, Tim Wicinksi, Paul Wouters, 674 and other members of the dnsop working group for their input. 676 10. Implementation Status 678 10.1. Authors' Implementation 680 The authors have an open source implementation in C, using the ldns 681 library [ldns-zone-digest]. This implementation is able to perform 682 the following functions: 684 o Read an input zone and output a zone with the ZONEMD placeholder. 686 o Compute zone digest over signed zone and update the ZONEMD record. 688 o Re-compute DNSSEC signature over the ZONEMD record. 690 o Verify the zone digest from an input zone. 692 This implementation does not: 694 o Perform DNSSEC validation of the ZONEMD record. 696 o Support the Gost digest algorithm. 698 o Output the ZONEMD record in its defined presentation format. 700 10.2. Shane Kerr's Implementation 702 Shane Kerr wrote an implementation of this specification during the 703 IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in 704 Python and is able to perform the following functions: 706 o Read an input zone and a output zone with ZONEMD record. 708 o Verify the zone digest from an input zone. 710 o Output the ZONEMD record in its defined presentation format. 712 o Generate Gost digests. 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 11. 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 12. References 824 12.1. Normative References 826 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 827 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 828 . 830 [RFC1035] Mockapetris, P., "Domain names - implementation and 831 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 832 November 1987, . 834 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 835 Requirement Levels", BCP 14, RFC 2119, 836 DOI 10.17487/RFC2119, March 1997, 837 . 839 [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS 840 Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, 841 . 843 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 844 Rose, "Resource Records for the DNS Security Extensions", 845 RFC 4034, DOI 10.17487/RFC4034, March 2005, 846 . 848 [RFC6605] Hoffman, P. and W. Wijngaards, "Elliptic Curve Digital 849 Signature Algorithm (DSA) for DNSSEC", RFC 6605, 850 DOI 10.17487/RFC6605, April 2012, 851 . 853 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 854 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 855 May 2017, . 857 12.2. Informative References 859 [CZDS] Internet Corporation for Assigned Names and Numbers, 860 "Centralized Zone Data Service", October 2018, 861 . 863 [dns-over-https] 864 Hoffman, P. and P. McManus, "DNS Queries over HTTPS 865 (DoH)", draft-ietf-doh-dns-over-https-12 (work in 866 progress), June 2018, . 869 [InterNIC] 870 ICANN, "InterNIC FTP site", May 2018, 871 . 873 [ldns-zone-digest] 874 Verisign, "Implementation of Message Digests for DNS Zones 875 using the ldns library", July 2018, 876 . 878 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 879 DOI 10.17487/RFC1995, August 1996, 880 . 882 [RFC2065] Eastlake 3rd, D. and C. Kaufman, "Domain Name System 883 Security Extensions", RFC 2065, DOI 10.17487/RFC2065, 884 January 1997, . 886 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 887 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 888 RFC 2136, DOI 10.17487/RFC2136, April 1997, 889 . 891 [RFC2535] Eastlake 3rd, D., "Domain Name System Security 892 Extensions", RFC 2535, DOI 10.17487/RFC2535, March 1999, 893 . 895 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 896 Wellington, "Secret Key Transaction Authentication for DNS 897 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 898 . 900 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 901 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 902 2000, . 904 [RFC3851] Ramsdell, B., Ed., "Secure/Multipurpose Internet Mail 905 Extensions (S/MIME) Version 3.1 Message Specification", 906 RFC 3851, DOI 10.17487/RFC3851, July 2004, 907 . 909 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 910 Thayer, "OpenPGP Message Format", RFC 4880, 911 DOI 10.17487/RFC4880, November 2007, 912 . 914 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 915 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 916 . 918 [RFC7706] Kumari, W. and P. Hoffman, "Decreasing Access Time to Root 919 Servers by Running One on Loopback", RFC 7706, 920 DOI 10.17487/RFC7706, November 2015, 921 . 923 [RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS 924 Terminology", RFC 7719, DOI 10.17487/RFC7719, December 925 2015, . 927 [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., 928 and P. Hoffman, "Specification for DNS over Transport 929 Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 930 2016, . 932 [RootServers] 933 Root Server Operators, "Root Server Technical Operations", 934 July 2018, . 936 [RPZ] Vixie, P. and V. Schryver, "DNS Response Policy Zones 937 (RPZ)", draft-vixie-dnsop-dns-rpz-00 (work in progress), 938 June 2018, . 941 [ZoneDigestHackathon] 942 Kerr, S., "Prototype implementation of ZONEMD for the IETF 943 102 hackathon in Python", July 2018, 944 . 946 Appendix A. Example Zones With Digests 948 This appendex contains example zones with accurate ZONEMD records. 949 These can be used to verify an implementation of the zone digest 950 protocol. 952 A.1. Simple EXAMPLE Zone 954 Here, the EXAMPLE zone contains an SOA record, NS and glue records, 955 and a ZONEMD record. 957 example. 86400 IN SOA ns1 admin 2018031900 ( 958 1800 900 604800 86400 ) 959 86400 IN NS ns1 960 86400 IN NS ns2 961 86400 IN ZONEMD 2018031900 1 0 ( 962 f32765ce15c50477 963 42a08be15d9a0efb 964 749417eaadcfa28b 965 1bf751b6bc49f9be 966 a615c4a386cfd6a5 967 d85e2d2182691249 ) 968 ns1 3600 IN A 127.0.0.1 969 ns2 3600 IN AAAA ::1 971 A.2. Complex EXAMPLE Zone 973 Here, the EXAMPLE zone contains duplicate RRs, and an occluded RR, 974 and one out-of-zone RR. 976 example. 86400 IN SOA ns1 admin 2018031900 ( 977 1800 900 604800 86400 ) 978 86400 IN NS ns1 979 86400 IN NS ns2 980 86400 IN ZONEMD 2018031900 1 0 ( 981 686a6d74d5638612 982 64ea4e6cc12c22d1 983 7ebc529791d393bd 984 e164a45390f714e9 985 9ede0d05a5644573 986 da4bbcc83744acf2 ) 987 ns1 3600 IN A 127.0.0.1 988 ns2 3600 IN AAAA ::1 989 occluded.sub 7200 IN TXT "I'm occluded but must be digested" 990 sub 7200 IN NS ns1 991 duplicate 300 IN TXT "I must be digested just once" 992 duplicate 300 IN TXT "I must be digested just once" 993 foo.test. 555 IN TXT "out-of-zone data must be excluded" 995 A.3. The URI.ARPA Zone 997 The URI.ARPA zone retreived 2018-10-21. 999 ; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr 1000 ; (2 servers found) 1001 ;; global options: +cmd 1002 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1003 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1004 uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 ( 1005 20181028142623 20181007205525 47155 uri.arpa. 1006 eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi 1007 /pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e 1008 HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= ) 1009 uri.arpa. 86400 IN RRSIG NS 8 2 86400 ( 1010 20181028172020 20181007175821 47155 uri.arpa. 1011 ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln 1012 4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF 1013 Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= ) 1014 uri.arpa. 600 IN RRSIG MX 8 2 600 ( 1015 20181028170556 20181007175821 47155 uri.arpa. 1016 e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t 1017 lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK 1018 A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= ) 1019 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1020 20181028152832 20181007175821 15796 uri.arpa. 1021 nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286 1022 XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V 1023 chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR 1024 6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B 1025 dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd 1026 uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk 1027 5R0A1w== ) 1028 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1029 20181028152832 20181007175821 55480 uri.arpa. 1030 lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X 1031 nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV 1032 63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj 1033 2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75 1034 WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R 1035 PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA 1036 1HeBfw== ) 1037 uri.arpa. 3600 IN RRSIG SOA 8 2 3600 ( 1038 20181029114753 20181008222815 47155 uri.arpa. 1039 qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2 1040 Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu 1041 9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= ) 1042 uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA ( 1043 MX RRSIG NSEC DNSKEY ) 1044 uri.arpa. 86400 IN NS a.iana-servers.net. 1045 uri.arpa. 86400 IN NS b.iana-servers.net. 1046 uri.arpa. 86400 IN NS c.iana-servers.net. 1047 uri.arpa. 86400 IN NS ns2.lacnic.net. 1048 uri.arpa. 86400 IN NS sec3.apnic.net. 1049 uri.arpa. 600 IN MX 10 pechora.icann.org. 1050 uri.arpa. 3600 IN DNSKEY 256 3 8 ( 1051 AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK 1052 uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL 1053 Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx 1054 SdJjlH0B ) 1055 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1056 AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY 1057 cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc 1058 3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/ 1059 Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9 1060 iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5 1061 ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt 1062 l3wpbp+Wpm8= ) 1063 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1064 AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR 1065 wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD 1066 FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG 1067 mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU 1068 7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3 1069 e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0 1070 xmJVvNQlwdE= ) 1072 ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1073 20181028080856 20181007175821 47155 uri.arpa. 1074 HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9 1075 jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP 1076 Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= ) 1077 ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1078 20181028103644 20181007205525 47155 uri.arpa. 1079 WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0 1080 9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5 1081 YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= ) 1082 ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR ( 1083 RRSIG NSEC ) 1084 ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1085 "!^ftp://([^:/?#]*).*$!\\1!i" . ) 1086 http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1087 20181029010647 20181007175821 47155 uri.arpa. 1088 U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE 1089 H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+ 1090 ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= ) 1091 http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1092 20181029011815 20181007205525 47155 uri.arpa. 1093 T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F 1094 Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0 1095 RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= ) 1096 http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR ( 1097 RRSIG NSEC ) 1098 http.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1099 "!^http://([^:/?#]*).*$!\\1!i" . ) 1100 mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1101 20181028110727 20181007175821 47155 uri.arpa. 1102 GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/ 1103 IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl 1104 fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= ) 1105 mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1106 20181028141825 20181007205525 47155 uri.arpa. 1107 MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF 1108 j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg 1109 916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= ) 1110 mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR ( 1111 RRSIG NSEC ) 1112 mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1113 "!^mailto:(.*)@(.*)$!\\2!i" . ) 1114 urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1115 20181028123243 20181007175821 47155 uri.arpa. 1116 Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe 1117 UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9 1118 DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= ) 1119 urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1120 20181029071816 20181007205525 47155 uri.arpa. 1121 ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS 1122 D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW 1123 BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= ) 1124 urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG ( 1125 NSEC ) 1126 urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1127 "/urn:([^:]+)/\\1/i" . ) 1128 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1129 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1130 ;; Query time: 66 msec 1131 ;; SERVER: 192.0.32.132#53(192.0.32.132) 1132 ;; WHEN: Sun Oct 21 20:39:28 UTC 2018 1133 ;; XFR size: 34 records (messages 1, bytes 3941) 1134 uri.arpa. 3600 IN ZONEMD 2018100702 1 0 ( 1135 80af7afd9540ff2c4c559f0d2b83393386304e093e0e66787378b2 1136 a578297b49b4dccb422bce2c300bb92b354575283a ) 1138 A.4. The ROOT-SERVERS.NET Zone 1140 The ROOT-SERVERS.NET zone retreived 2018-10-21. 1142 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1143 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1144 root-servers.net. 3600000 IN NS a.root-servers.net. 1145 root-servers.net. 3600000 IN NS b.root-servers.net. 1146 root-servers.net. 3600000 IN NS c.root-servers.net. 1147 root-servers.net. 3600000 IN NS d.root-servers.net. 1148 root-servers.net. 3600000 IN NS e.root-servers.net. 1149 root-servers.net. 3600000 IN NS f.root-servers.net. 1150 root-servers.net. 3600000 IN NS g.root-servers.net. 1151 root-servers.net. 3600000 IN NS h.root-servers.net. 1152 root-servers.net. 3600000 IN NS i.root-servers.net. 1153 root-servers.net. 3600000 IN NS j.root-servers.net. 1154 root-servers.net. 3600000 IN NS k.root-servers.net. 1155 root-servers.net. 3600000 IN NS l.root-servers.net. 1156 root-servers.net. 3600000 IN NS m.root-servers.net. 1157 a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30 1158 a.root-servers.net. 3600000 IN A 198.41.0.4 1159 b.root-servers.net. 3600000 IN MX 20 mail.isi.edu. 1160 b.root-servers.net. 3600000 IN AAAA 2001:500:200::b 1161 b.root-servers.net. 3600000 IN A 199.9.14.201 1162 c.root-servers.net. 3600000 IN AAAA 2001:500:2::c 1163 c.root-servers.net. 3600000 IN A 192.33.4.12 1164 d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d 1165 d.root-servers.net. 3600000 IN A 199.7.91.13 1166 e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e 1167 e.root-servers.net. 3600000 IN A 192.203.230.10 1168 f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f 1169 f.root-servers.net. 3600000 IN A 192.5.5.241 1170 g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d 1171 g.root-servers.net. 3600000 IN A 192.112.36.4 1172 h.root-servers.net. 3600000 IN AAAA 2001:500:1::53 1173 h.root-servers.net. 3600000 IN A 198.97.190.53 1174 i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org. 1175 i.root-servers.net. 3600000 IN AAAA 2001:7fe::53 1176 i.root-servers.net. 3600000 IN A 192.36.148.17 1177 j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30 1178 j.root-servers.net. 3600000 IN A 192.58.128.30 1179 k.root-servers.net. 3600000 IN AAAA 2001:7fd::1 1180 k.root-servers.net. 3600000 IN A 193.0.14.129 1181 l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42 1182 l.root-servers.net. 3600000 IN A 199.7.83.42 1183 m.root-servers.net. 3600000 IN AAAA 2001:dc3::35 1184 m.root-servers.net. 3600000 IN A 202.12.27.33 1185 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1186 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1187 root-servers.net. 3600000 IN ZONEMD 2018091100 1 0 ( 1188 aadf7a017bccd8cefe6040494800249fd5edc3d49e2e8ce8db7522f47f 1189 97f168db794bf5f679fbe0c8433fb66f7a0c26 ) 1191 Authors' Addresses 1193 Duane Wessels 1194 Verisign 1195 12061 Bluemont Way 1196 Reston, VA 20190 1198 Phone: +1 703 948-3200 1199 Email: dwessels@verisign.com 1200 URI: http://verisign.com 1202 Piet Barber 1203 Verisign 1204 12061 Bluemont Way 1205 Reston, VA 20190 1207 Phone: +1 703 948-3200 1208 Email: pbarber@verisign.com 1209 URI: http://verisign.com 1211 Matt Weinberg 1212 Verisign 1213 12061 Bluemont Way 1214 Reston, VA 20190 1216 Phone: +1 703 948-3200 1217 Email: mweinberg@verisign.com 1218 URI: http://verisign.com 1220 Warren Kumari 1221 Google 1222 1600 Amphitheatre Parkway 1223 Mountain View, CA 94043 1225 Email: warren@kumari.net 1227 Wes Hardaker 1228 USC/ISI 1229 P.O. Box 382 1230 Davis, CA 95617 1232 Email: ietf@hardakers.net