idnits 2.17.1 draft-ietf-dnsop-extended-error-11.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (September 30, 2019) is 1642 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-10) exists of draft-ietf-dnsop-serve-stale-08 ** Obsolete normative reference: RFC 2434 (Obsoleted by RFC 5226) ** Obsolete normative reference: RFC 2671 (Obsoleted by RFC 6891) -- Obsolete informational reference (is this intentional?): RFC 2845 (Obsoleted by RFC 8945) Summary: 2 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group W. Kumari 3 Internet-Draft Google 4 Intended status: Standards Track E. Hunt 5 Expires: April 2, 2020 ISC 6 R. Arends 7 ICANN 8 W. Hardaker 9 USC/ISI 10 D. Lawrence 11 Oracle + Dyn 12 September 30, 2019 14 Extended DNS Errors 15 draft-ietf-dnsop-extended-error-11 17 Abstract 19 This document defines an extensible method to return additional 20 information about the cause of DNS errors. Though created primarily 21 to extend SERVFAIL to provide additional information about the cause 22 of DNS and DNSSEC failures, the Extended DNS Errors option defined in 23 this document allows all response types to contain extended error 24 information. Extended DNS Error information does not change the 25 processing of RCODEs. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at http://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on April 2, 2020. 44 Copyright Notice 46 Copyright (c) 2019 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (http://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction and background . . . . . . . . . . . . . . . . . 3 62 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 4 63 2. Extended Error EDNS0 option format . . . . . . . . . . . . . 4 64 3. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5 65 3.1. Extended DNS Error Code 0 - Other . . . . . . . . . . . . 5 66 3.2. Extended DNS Error Code 1 - 67 Unsupported DNSKEY Algorithm . . . . . . . . . . . . . . 5 68 3.3. Extended DNS Error Code 2 - Unsupported DS 69 Digest Type . . . . . . . . . . . . . . . . . . . . . . . 5 70 3.4. Extended DNS Error Code 3 - Stale Answer . . . . . . . . 5 71 3.5. Extended DNS Error Code 4 - Forged Answer . . . . . . . . 5 72 3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate . . . . 6 73 3.7. Extended DNS Error Code 6 - DNSSEC Bogus . . . . . . . . 6 74 3.8. Extended DNS Error Code 7 - Signature Expired . . . . . . 6 75 3.9. Extended DNS Error Code 8 - Signature Not Yet Valid . . . 6 76 3.10. Extended DNS Error Code 9 - DNSKEY Missing . . . . . . . 6 77 3.11. Extended DNS Error Code 10 - RRSIGs Missing . . . . . . . 6 78 3.12. Extended DNS Error Code 11 - No Zone Key Bit Set . . . . 6 79 3.13. Extended DNS Error Code 12 - NSEC Missing . . . . . . . . 6 80 3.14. Extended DNS Error Code 13 - Cached Error . . . . . . . . 7 81 3.15. Extended DNS Error Code 14 - Not Ready . . . . . . . . . 7 82 3.16. Extended DNS Error Code 15 - Blocked . . . . . . . . . . 7 83 3.17. Extended DNS Error Code 16 - Censored . . . . . . . . . . 7 84 3.18. Extended DNS Error Code 17 - Filtered . . . . . . . . . . 7 85 3.19. Extended DNS Error Code 18 - Prohibited . . . . . . . . . 7 86 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer . . . 7 87 3.21. Extended DNS Error Code 20 - Not Authoritative . . . . . 8 88 3.22. Extended DNS Error Code 21 - Not Supported . . . . . . . 8 89 3.23. Extended DNS Error Code 22 - No Reachable Authority . . . 8 90 3.24. Extended DNS Error Code 23 - Network Error . . . . . . . 8 91 3.25. Extended DNS Error Code 24 - Invalid Data . . . . . . . . 8 92 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 93 4.1. A New Extended DNS Error Code EDNS Option . . . . . . . . 8 94 4.2. New Registry Table for Extended DNS Error Codes . . . . . 8 95 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 96 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 97 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 98 7.1. Normative References . . . . . . . . . . . . . . . . . . 12 99 7.2. Informative References . . . . . . . . . . . . . . . . . 12 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 102 1. Introduction and background 104 There are many reasons that a DNS query may fail, some of them 105 transient, some permanent; some can be resolved by querying another 106 server, some are likely best handled by stopping resolution. 107 Unfortunately, the error signals that a DNS server can return are 108 very limited, and are not very expressive. This means that 109 applications and resolvers often have to "guess" at what the issue is 110 - e.g. was the answer marked REFUSED because of a lame delegation, or 111 because the nameserver is still starting up and loading zones? Is a 112 SERVFAIL a DNSSEC validation issue, or is the nameserver experiencing 113 some other failure? What error messages should be presented to the 114 user or logged under these conditions? 116 A good example of issues that would benefit by additional error 117 information are errors caused by DNSSEC validation issues. When a 118 stub resolver queries a name which is DNSSEC bogus (using a 119 validating resolver), the stub resolver receives only a SERVFAIL in 120 response. Unfortunately, the SERVFAIL Response Code (RCODE) is used 121 to signal many sorts of DNS errors, and so the stub resolvers only 122 option is to ask the next configured DNS resolver. The result of 123 trying the next resolver is one of two outcomes: either the next 124 resolver also validates, and a SERVFAIL is returned again or the next 125 resolver is not a validating resolver, and the user is returned a 126 potentially harmful result. With an Extended DNS Error (EDE) option 127 enclosed in the response message, the resolver is able to return a 128 more descriptive reason as to why any failures happened, or add 129 additional context to a message containing a NOERROR RCODE. 131 This document specifies a mechanism to extend DNS errors to provide 132 additional information about the cause of an error. These extended 133 DNS error codes described in this document and can be used by any 134 system that sends DNS queries and receives a response containing an 135 EDE option. Different codes are useful in different circumstances, 136 and thus different systems (stub resolvers, recursive resolvers, and 137 authoritative resolvers) might receive and use them. 139 This document does not allow or prohibit any particular extended 140 error codes and information to be matched with any particular RCODEs. 141 Some combinations of extended error codes and RCODEs may seem 142 nonsensical (such as resolver-specific extended error codes in 143 responses from authoritative servers), so systems interpreting the 144 extended error codes MUST NOT assume that a combination will make 145 sense. Receivers MUST be able to accept EDE codes and EXTRA-TEXT in 146 all messages, including those with a NOERROR RCODE. Applications 147 MUST continue to follow requirements from applicable specs on how to 148 process RCODEs no matter what EDE values is also received 150 1.1. Requirements notation 152 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 153 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 154 document are to be interpreted as described in [RFC2119]. 156 2. Extended Error EDNS0 option format 158 This draft uses an EDNS0 ([RFC2671]) option to include Extended DNS 159 Error (EDE) information in DNS messages. The option is structured as 160 follows: 162 1 1 1 1 1 1 163 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 164 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 165 0: | OPTION-CODE | 166 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 167 2: | OPTION-LENGTH | 168 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 169 4: | INFO-CODE | 170 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 171 6: / EXTRA-TEXT ... / 172 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 174 Field definition details: 176 o OPTION-CODE, 2-octets/16-bits (defined in [RFC6891]]), for EDE is 177 TBD. [RFC Editor: change TBD to the proper code once assigned by 178 IANA.] 179 o OPTION-LENGTH, 2-octets/16-bits ((defined in [RFC6891]]) contains 180 the length of the payload (everything after OPTION-LENGTH) in 181 octets and should be 4 plus the length of the EXTRA-TEXT section 182 (which may be a zero-length string). 183 o INFO-CODE, 16-bits, which is the principal contribution of this 184 document. This 16-bit value, encoded in network (MSB) byte order, 185 provides the additional context for the RESPONSE-CODE of the DNS 186 message. The INFO-CODE serves as an index into the "Extended DNS 187 Errors" registry Section 4.1. 188 o EXTRA-TEXT, a variable length, UTF-8 encoded, text field that may 189 hold additional textual information. Note: EXTRA-TEXT may be zero 190 octets in length, indicating there is no EXTRA-TEXT included. 191 Care should be taken not to leak private information that an 192 observer would not otherwise have access to, such as account 193 numbers. 195 The Extended DNS Error (EDE) option can be included in any response 196 (SERVFAIL, NXDOMAIN, REFUSED, and even NOERROR, etc) to a query that 197 includes OPT Pseudo-RR [RFC6891]. This document includes a set of 198 initial codepoints (and requests to the IANA to add them to the 199 registry), but is extensible via the IANA registry to allow 200 additional error and information codes to be defined in the future. 202 3. Defined Extended DNS Errors 204 This document defines some initial EDE codes. The mechanism is 205 intended to be extensible, and additional code-points can be 206 registered in the "Extended DNS Errors" registry Section 4.1. The 207 INFO-CODE from the EDE EDNS option is used to serve as an index into 208 the "Extended DNS Error" IANA registry, the initial values for which 209 are defined in the following sub-sections. 211 3.1. Extended DNS Error Code 0 - Other 213 The error in question falls into a category that does not match known 214 extended error codes. Implementations SHOULD include a EXTRA-TEXT 215 value to augment this error code with additional information. 217 3.2. Extended DNS Error Code 1 - Unsupported DNSKEY Algorithm 219 The resolver attempted to perform DNSSEC validation, but a DNSKEY 220 RRSET contained only unsupported DNSSEC algorithms. 222 3.3. Extended DNS Error Code 2 - Unsupported DS Digest Type 224 The resolver attempted to perform DNSSEC validation, but a DS RRSET 225 contained only unsupported Digest Types. 227 3.4. Extended DNS Error Code 3 - Stale Answer 229 The resolver was unable to resolve answer within its time limits and 230 decided to answer with previously cached data instead of answering 231 with an error. This is typically caused by problems communicating 232 with an authoritative serever, possibly as result of a DoS attack 233 against another network. 235 3.5. Extended DNS Error Code 4 - Forged Answer 237 For policy reasons (legal obligation, or malware filtering, for 238 instance), an answer was forged. Note that this should be used when 239 an answer is still provided, not when failure codes are returned 240 instead. See Blocked(15), Censored (16), and Filtered (17) for use 241 when returning other response codes. 243 3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate 245 The resolver attempted to perform DNSSEC validation, but validation 246 ended in the Indeterminate state [RFC4035]. 248 3.7. Extended DNS Error Code 6 - DNSSEC Bogus 250 The resolver attempted to perform DNSSEC validation, but validation 251 ended in the Bogus state. 253 3.8. Extended DNS Error Code 7 - Signature Expired 255 The resolver attempted to perform DNSSEC validation, but no 256 signatures are presently valid and some (often all) are expired. 258 3.9. Extended DNS Error Code 8 - Signature Not Yet Valid 260 The resolver attempted to perform DNSSEC validation, but but no 261 signatures are presently valid and at least some are not yet valid. 263 3.10. Extended DNS Error Code 9 - DNSKEY Missing 265 A DS record existed at a parent, but no supported matching DNSKEY 266 record could be found for the child. 268 3.11. Extended DNS Error Code 10 - RRSIGs Missing 270 The resolver attempted to perform DNSSEC validation, but no RRSIGs 271 could be found for at least one RRset where RRSIGs were expected. 273 3.12. Extended DNS Error Code 11 - No Zone Key Bit Set 275 The resolver attempted to perform DNSSEC validation, but no Zone Key 276 Bit was set in a DNSKEY. 278 3.13. Extended DNS Error Code 12 - NSEC Missing 280 The resolver attempted to perform DNSSEC validation, but the 281 requested data was missing and a covering NSEC or NSEC3 was not 282 provided. 284 3.14. Extended DNS Error Code 13 - Cached Error 286 The resolver is returning the SERVFAIL RCODE from its cache. 288 3.15. Extended DNS Error Code 14 - Not Ready 290 The server is unable to answer the query as it is not fully 291 functional (yet). 293 3.16. Extended DNS Error Code 15 - Blocked 295 The server is unable to respond to the request because the domain is 296 blacklisted due to an internal security policy imposed by the 297 operator of the server being directly talked to. 299 3.17. Extended DNS Error Code 16 - Censored 301 The server is unable to respond to the request because the domain is 302 blacklisted by a security policy imposed upon the server being talked 303 to by an external requirement. Note that how the imposed policy is 304 applied is irrelevant (in-band DNS filtering, court order, etc). 306 3.18. Extended DNS Error Code 17 - Filtered 308 The server is unable to respond to the request because the domain is 309 blacklisted as requested by the client. Functionally, this amounts 310 to "you requested that we filter domains like this one." 312 3.19. Extended DNS Error Code 18 - Prohibited 314 An authoritative or recursive resolver that receives a query from an 315 "unauthorized" client can annotate its REFUSED message with this 316 code. Examples of "unauthorized" clients are recursive queries from 317 IP addresses outside the network, blacklisted IP addresses, local 318 policy, etc. 320 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer 322 The resolver was unable to resolve an answer within its configured 323 time limits and decided to answer with a previously cached NXDOMAIN 324 answer instead of answering with an error. This is may be caused, 325 for example, by problems communicating with an authoritative server, 326 possibly as result of a DoS attack against another network. 328 3.21. Extended DNS Error Code 20 - Not Authoritative 330 An authoritative server that receives a query (with the RD bit clear, 331 or when not configured for recursion) for a domain for which it is 332 not authoritative SHOULD include this EDE code in the REFUSED 333 response. A resolver that receives a query (with the RD bit clear) 334 SHOULD include this EDE code in the REFUSED response. 336 3.22. Extended DNS Error Code 21 - Not Supported 338 The requested operation or query is not supported as its use has been 339 deprecated. 341 3.23. Extended DNS Error Code 22 - No Reachable Authority 343 The resolver could not reach any of the authoritative name servers 344 (or they refused to reply). 346 3.24. Extended DNS Error Code 23 - Network Error 348 An unrecoverable error occurred while communicating with another 349 server. 351 3.25. Extended DNS Error Code 24 - Invalid Data 353 An authoritative server that cannot answer with data for a zone it is 354 otherwise configured to support. This may occur because its most 355 recent zone is too old, or has expired, for example. 357 4. IANA Considerations 359 4.1. A New Extended DNS Error Code EDNS Option 361 This document defines a new EDNS(0) option, entitled "Extended DNS 362 Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes 363 (OPT)" registry [to be removed upon publication: 364 [http://www.iana.org/assignments/dns-parameters/dns- 365 parameters.xhtml#dns-parameters-11] 367 Value Name Status Reference 368 ----- ---------------- ------ ------------------ 369 TBD Extended DNS Error TBD [ This document ] 371 4.2. New Registry Table for Extended DNS Error Codes 373 This document defines a new IANA registry table, where the index 374 value is the INFO-CODE from the "Extended DNS Error" EDNS option 375 defined in this document. The IANA is requested to create and 376 maintain this "Extended DNS Error" codes registry. The code-point 377 space for the INFO-CODE index is to be broken into 3 ranges: 379 o 0 - 32767: Expert Review [RFC2434]. 380 o 32768 - 49151: First come, first served. 381 o 49152 - 65535: Experimental / Private use. 383 A starting set of entries, based on the contents of this document, is 384 as follows: 386 INFO-CODE: 0 387 Purpose: Other Error 388 Reference: Section 3.1 390 INFO-CODE: 1 391 Purpose: Unsupported DNSKEY Algorithm 392 Reference: Section 3.2 394 INFO-CODE: 2 395 Purpose: Unsupported DS Digest Type 396 Reference: Section 3.3 398 INFO-CODE: 3 399 Purpose: Stale Answer 400 Reference: Section 3.4, [I-D.ietf-dnsop-serve-stale] 402 INFO-CODE: 4 403 Purpose: Forged Answer 404 Reference: Section 3.5 406 INFO-CODE: 5 407 Purpose: DNSSEC Indeterminate 408 Reference: Section 3.6 410 INFO-CODE: 6 411 Purpose: DNSSEC Bogus 412 Reference: Section 3.7 414 INFO-CODE: 7 415 Purpose: Signature Expired 416 Reference: Section 3.8 418 INFO-CODE: 8 419 Purpose: Signature Not Yet Valid 420 Reference: Section 3.9 422 INFO-CODE: 9 423 Purpose: DNSKEY Missing 424 Reference: Section 3.10 426 INFO-CODE: 10 427 Purpose: RRSIGs Missing 428 Reference: Section 3.11 430 INFO-CODE: 11 431 Purpose: No Zone Key Bit Set 432 Reference: Section 3.12 434 INFO-CODE: 12 435 Purpose: NSEC Missing 436 Reference: Section 3.13 438 INFO-CODE: 13 439 Purpose: Cached Error 440 Reference: Section 3.14 442 INFO-CODE: 14 443 Purpose: Not Ready. 444 Reference: Section 3.15 446 INFO-CODE: 15 447 Purpose: Blocked 448 Reference: Section 3.16 450 INFO-CODE: 16 451 Purpose: Censored 452 Reference: Section 3.17 454 INFO-CODE: 17 455 Purpose: Filtered 456 Reference: Section 3.18 458 INFO-CODE: 18 459 Purpose: Prohibited 460 Reference: Section 3.19 462 INFO-CODE: 19 463 Purpose: Stale NXDomain Answer 464 Reference: Section 3.20 466 INFO-CODE: 20 467 Purpose: Not Authoritative 468 Reference: Section 3.21 470 INFO-CODE: 21 471 Purpose: Not Supported 472 Reference: Section 3.22 474 INFO-CODE: 22 475 Purpose: No Reachable Authority 476 Reference: Section 3.23 478 INFO-CODE: 23 479 Purpose: Network Error 480 Reference: Section 3.24 482 INFO-CODE: 24 483 Purpose: Invalid Data 484 Reference: Section 3.25 486 5. Security Considerations 488 Though DNSSEC continues to be deployed, unfortunately a significant 489 number of clients (~11% according to [GeoffValidation]) that receive 490 a SERVFAIL from a validating resolver because of a DNSSEC validaion 491 issue will simply ask the next (potentially non-validating) resolver 492 in their list, and thus don't get any of the protections which DNSSEC 493 should provide. 495 This information is unauthenticated information, and an attacker (e.g 496 a MITM or malicious recursive server) could insert an extended error 497 response into already untrusted data -- ideally clients and resolvers 498 would not trust any unauthenticated information, but until we live in 499 an era where all DNS answers are authenticated via DNSSEC or other 500 mechanisms [RFC2845] [RFC8094], there are some tradeoffs. As an 501 example, an attacker who is able to insert the DNSSEC Bogus Extended 502 Error into a packet could instead simply reply with a fictitious 503 address (A or AAAA) record. Note that DNS Response Codes also 504 contain no authentication and can be just as easily manipulated. 506 6. Acknowledgements 508 The authors wish to thank Joe Abley, Mark Andrews, Tim April, 509 Vittorio Bertola, Stephane Bortzmeyer, Vladimir Cunat, Ralph Dolmans, 510 Peter DeVries, Peter van Dijk, Mats Dufberg, Donald Eastlake, Bob 511 Harold, Paul Hoffman, Geoff Huston, Shane Kerr, Edward Lewis, Carlos 512 M. Martinez, George Michelson, Eric Orth, Michael Sheldon, Puneet 513 Sood, Petr Spacek, Ondrej Sury, John Todd, Loganaden Velvindron, and 514 Paul Vixie. They also vaguely remember discussing this with a number 515 of people over the years, but have forgotten who all they were -- if 516 you were one of them, and are not listed, please let us know and 517 we'll acknowledge you. 519 One author also wants to thank the band "Infected Mushroom" for 520 providing a good background soundtrack (and to see if he can get away 521 with this in an RFC!) Another author would like to thank the band 522 "Mushroom Infectors". This was funny at the time we wrote it, but we 523 cannot remember why... 525 7. References 527 7.1. Normative References 529 [I-D.ietf-dnsop-serve-stale] 530 Lawrence, D., Kumari, W., and P. Sood, "Serving Stale Data 531 to Improve DNS Resiliency", draft-ietf-dnsop-serve- 532 stale-08 (work in progress), September 2019. 534 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 535 Requirement Levels", BCP 14, RFC 2119, 536 DOI 10.17487/RFC2119, March 1997, . 539 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 540 IANA Considerations Section in RFCs", RFC 2434, 541 DOI 10.17487/RFC2434, October 1998, . 544 [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", 545 RFC 2671, DOI 10.17487/RFC2671, August 1999, 546 . 548 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 549 Rose, "Protocol Modifications for the DNS Security 550 Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, 551 . 553 [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms 554 for DNS (EDNS(0))", STD 75, RFC 6891, 555 DOI 10.17487/RFC6891, April 2013, . 558 7.2. Informative References 560 [GeoffValidation] 561 IANA, "A quick review of DNSSEC Validation in today's 562 Internet", June 2016, . 565 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 566 Wellington, "Secret Key Transaction Authentication for DNS 567 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 568 . 570 [RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram 571 Transport Layer Security (DTLS)", RFC 8094, 572 DOI 10.17487/RFC8094, February 2017, . 575 Authors' Addresses 577 Warren Kumari 578 Google 579 1600 Amphitheatre Parkway 580 Mountain View, CA 94043 581 US 583 Email: warren@kumari.net 585 Evan Hunt 586 ISC 587 950 Charter St 588 Redwood City, CA 94063 589 US 591 Email: each@isc.org 593 Roy Arends 594 ICANN 596 Email: roy.arends@icann.org 598 Wes Hardaker 599 USC/ISI 600 P.O. Box 382 601 Davis, CA 95617 602 US 604 Email: ietf@hardakers.net 605 David C Lawrence 606 Oracle + Dyn 607 150 Dow St 608 Manchester, NH 03101 609 US 611 Email: tale@dd.org