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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-10) exists of draft-ietf-dnsop-serve-stale-08 ** Obsolete normative reference: RFC 2434 (Obsoleted by RFC 5226) ** Obsolete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: March 30, 2020 ISC 6 R. Arends 7 ICANN 8 W. Hardaker 9 USC/ISI 10 D. Lawrence 11 Oracle + Dyn 12 September 27, 2019 14 Extended DNS Errors 15 draft-ietf-dnsop-extended-error-10 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 March 30, 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 . . . . . . . . 6 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 17 - Prohibited . . . . . . . . . 7 86 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer . . . 7 87 3.21. Extended DNS Error Code 20 - Not Authoritative . . . . . 7 88 3.22. Extended DNS Error Code 21 - Deprecated . . . . . . . . . 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? 115 A good example of issues that would benefit by additional error 116 information are errors caused by DNSSEC validation issues. When a 117 stub resolver queries a name which is DNSSEC bogus (using a 118 validating resolver), the stub resolver receives only a SERVFAIL in 119 response. Unfortunately, the SERVFAIL Response Code (RCODE) is used 120 to signal many sorts of DNS errors, and so the stub resolvers only 121 option is to ask the next configured DNS resolver. The result of 122 trying the next resolver is one of two outcomes: either the next 123 resolver also validates, and a SERVFAIL is returned again or the next 124 resolver is not a validating resolver, and the user is returned a 125 potentially harmful result. With an Extended DNS Error (EDE) option 126 enclosed in the response message, the resolver is able to return a 127 more descriptive reason as to why any failures happened, or add 128 additional context to a message containing a NOERROR RCODE. 130 This document specifies a mechanism to extend DNS errors to provide 131 additional information about the cause of an error. These extended 132 DNS error codes described in this document and can be used by any 133 system that sends DNS queries and receives a response containing an 134 EDE option. Different codes are useful in different circumstances, 135 and thus different systems (stub resolvers, recursive resolvers, and 136 authoritative resolvers) might receive and use them. 138 This document does not allow or prohibit any particular extended 139 error codes and information to be matched with any particular RCODEs. 140 Some combinations of extended error codes and RCODEs may seem 141 nonsensical (such as resolver-specific extended error codes in 142 responses from authoritative servers), so systems interpreting the 143 extended error codes MUST NOT assume that a combination will make 144 sense. Receivers MUST be able to accept EDE codes and EXTRA-TEXT in 145 all messages, including those with a NOERROR RCODE. Receivers MUST 146 NOT change the processing of RCODEs in messages based on extended 147 error codes. 149 1.1. Requirements notation 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 153 document are to be interpreted as described in [RFC2119]. 155 2. Extended Error EDNS0 option format 157 This draft uses an EDNS0 ([RFC2671]) option to include Extended DNS 158 Error (EDE) information in DNS messages. The option is structured as 159 follows: 161 1 1 1 1 1 1 162 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 163 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 164 0: | OPTION-CODE | 165 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 166 2: | OPTION-LENGTH | 167 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 168 4: | INFO-CODE | 169 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 170 6: / EXTRA-TEXT ... / 171 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 173 Field definition details: 175 o OPTION-CODE, 2 octets (defined in [RFC6891]]), for EDE is TBD. 176 [RFC Editor: change TBD to the proper code once assigned by IANA.] 177 o OPTION-LENGTH, 2 octets ((defined in [RFC6891]]) contains the 178 length of the payload (everything after OPTION-LENGTH) in octets 179 and should be 4 plus the length of the EXTRA-TEXT section (which 180 may be a zero-length string). 181 o INFO-CODE, 16-bits, which is the principal contribution of this 182 document. This 16-bit value, encoded in network (MSB) byte order, 183 provides the additional context for the RESPONSE-CODE of the DNS 184 message. The INFO-CODE serves as an index into the "Extended DNS 185 Errors" registry Section 4.1. 186 o EXTRA-TEXT, a variable length, UTF-8 encoded, text field that may 187 hold additional textual information. Note: EXTRA-TEXT may be zero 188 octets in length, indicating there is no EXTRA-TEXT included. 189 Care should be taken not to leak private information that an 190 observer would not otherwise have access to, such as account 191 numbers. 193 The Extended DNS Error (EDE) option can be included in any response 194 (SERVFAIL, NXDOMAIN, REFUSED, and even NOERROR, etc) to a query that 195 includes OPT Pseudo-RR [RFC6891]. This document includes a set of 196 initial codepoints (and requests to the IANA to add them to the 197 registry), but is extensible via the IANA registry to allow 198 additional error and information codes to be defined in the future. 200 3. Defined Extended DNS Errors 202 This document defines some initial EDE codes. The mechanism is 203 intended to be extensible, and additional code-points can be 204 registered in the "Extended DNS Errors" registry Section 4.1. The 205 INFO-CODE from the EDE EDNS option is used to serve as an index into 206 the "Extended DNS Error" IANA registry, the initial values for which 207 are defined in the following sub-sections. 209 3.1. Extended DNS Error Code 0 - Other 211 The error in question falls into a category that does not match known 212 extended error codes. Implementations SHOULD include a EXTRA-TEXT 213 value to augment this error code with additional information. 215 3.2. Extended DNS Error Code 1 - Unsupported DNSKEY Algorithm 217 The resolver attempted to perform DNSSEC validation, but a DNSKEY 218 RRSET contained only unsupported DNSSEC algorithms. 220 3.3. Extended DNS Error Code 2 - Unsupported DS Digest Type 222 The resolver attempted to perform DNSSEC validation, but a DS RRSET 223 contained only unsupported Digest Types. 225 3.4. Extended DNS Error Code 3 - Stale Answer 227 The resolver was unable to resolve answer within its time limits and 228 decided to answer with previously cached data instead of answering 229 with an error. This is typically caused by problems communicating 230 with an authoritative serever, possibly as result of a DoS attack 231 against another network. 233 3.5. Extended DNS Error Code 4 - Forged Answer 235 For policy reasons (legal obligation, or malware filtering, for 236 instance), an answer was forged. Note that this should be used when 237 an answer is still provided, not when failure codes are returned 238 instead. See Blocked(15), Censored (16), and Filtered (17) for use 239 when returning other response codes. 241 3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate 243 The resolver attempted to perform DNSSEC validation, but validation 244 ended in the Indeterminate state [RFC4035]. 246 3.7. Extended DNS Error Code 6 - DNSSEC Bogus 248 The resolver attempted to perform DNSSEC validation, but validation 249 ended in the Bogus state. 251 3.8. Extended DNS Error Code 7 - Signature Expired 253 The resolver attempted to perform DNSSEC validation, but all 254 signatures in an RRset in the validation chain were expired. 256 3.9. Extended DNS Error Code 8 - Signature Not Yet Valid 258 The resolver attempted to perform DNSSEC validation, but all the 259 signatures received were not yet valid. 261 3.10. Extended DNS Error Code 9 - DNSKEY Missing 263 A DS record existed at a parent, but no supported matching DNSKEY 264 record could be found for the child. 266 3.11. Extended DNS Error Code 10 - RRSIGs Missing 268 The resolver attempted to perform DNSSEC validation, but no RRSIGs 269 could be found for at least one RRset where RRSIGs were expected. 271 3.12. Extended DNS Error Code 11 - No Zone Key Bit Set 273 The resolver attempted to perform DNSSEC validation, but no Zone Key 274 Bit was set in a DNSKEY. 276 3.13. Extended DNS Error Code 12 - NSEC Missing 278 The resolver attempted to perform DNSSEC validation, but the 279 requested data was missing and a covering NSEC or NSEC3 was not 280 provided. 282 3.14. Extended DNS Error Code 13 - Cached Error 284 The resolver has Cached SERVFAIL for this query. 286 3.15. Extended DNS Error Code 14 - Not Ready 288 The server is unable to answer the query as it is not fully 289 functional (yet). 291 3.16. Extended DNS Error Code 15 - Blocked 293 The server is unable to respond to the request because the domain is 294 blacklisted due to an internal security policy imposed by the 295 operator of the server being directly talked to. 297 3.17. Extended DNS Error Code 16 - Censored 299 The server is unable to respond to the request because the domain is 300 blacklisted by a security policy imposed upon the server being talked 301 to by an external requirement. Note that how the imposed policy is 302 applied is irrelevant (in-band DNS filtering, court order, etc). 304 3.18. Extended DNS Error Code 17 - Filtered 306 The server is unable to respond to the request because the domain is 307 blacklisted as requested by the client. Functionally, this amounts 308 to "you requested that we filter domains like this one." 310 3.19. Extended DNS Error Code 17 - Prohibited 312 An authoritative or recursive resolver that receives a query from an 313 "unauthorized" client can annotate its REFUSED message with this 314 code. Examples of "unauthorized" clients are recursive queries from 315 IP addresses outside the network, blacklisted IP addresses, local 316 policy, etc. 318 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer 320 The resolver was unable to resolve an answer within its configured 321 time limits and decided to answer with a previously cached NXDOMAIN 322 answer instead of answering with an error. This is typically caused 323 by problems communicating with an authoritative server, possibly as 324 result of a DoS attack against another network. 326 3.21. Extended DNS Error Code 20 - Not Authoritative 328 An authoritative server that receives a query (with the RD bit clear, 329 or when not configured for recursion) for a domain for which it is 330 not authoritative SHOULD include this EDE code in the REFUSED 331 response. A resolver that receives a query (with the RD bit clear) 332 SHOULD include this EDE code in the REFUSED response. 334 3.22. Extended DNS Error Code 21 - Deprecated 336 The requested operation or query is not supported as its use has been 337 deprecated. 339 3.23. Extended DNS Error Code 22 - No Reachable Authority 341 The resolver could not reach any of the authoritative name servers 342 (or they refused to reply). 344 3.24. Extended DNS Error Code 23 - Network Error 346 An unrecoverable error occurred while communicating with another 347 server. 349 3.25. Extended DNS Error Code 24 - Invalid Data 351 An authoritative server that cannot answer with data for a zone it is 352 otherwise configured to support. This may occur because its most 353 recent zone is too old, or has expired, for example. 355 4. IANA Considerations 357 4.1. A New Extended DNS Error Code EDNS Option 359 This document defines a new EDNS(0) option, entitled "Extended DNS 360 Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes 361 (OPT)" registry [to be removed upon publication: 362 [http://www.iana.org/assignments/dns-parameters/dns- 363 parameters.xhtml#dns-parameters-11] 365 Value Name Status Reference 366 ----- ---------------- ------ ------------------ 367 TBD Extended DNS Error TBD [ This document ] 369 4.2. New Registry Table for Extended DNS Error Codes 371 This document defines a new IANA registry table, where the index 372 value is the INFO-CODE from the "Extended DNS Error" EDNS option 373 defined in this document. The IANA is requested to create and 374 maintain this "Extended DNS Error" codes registry. The code-point 375 space for the INFO-CODE index is to be broken into 3 ranges: 377 o 0 - 32767: Expert Review [RFC2434]. 378 o 32768 - 49151: First come, first served. 379 o 49152 - 65535: Experimental / Private use. 381 A starting set of entries, based on the contents of this document, is 382 as follows: 384 INFO-CODE: 0 385 Purpose: Other Error 386 Reference: Section 3.1 388 INFO-CODE: 1 389 Purpose: Unsupported DNSKEY Algorithm 390 Reference: Section 3.2 392 INFO-CODE: 2 393 Purpose: Unsupported DS Digest Type 394 Reference: Section 3.3 396 INFO-CODE: 3 397 Purpose: Stale Answer 398 Reference: Section 3.4, [I-D.ietf-dnsop-serve-stale] 400 INFO-CODE: 4 401 Purpose: Forged Answer 402 Reference: Section 3.5 404 INFO-CODE: 5 405 Purpose: DNSSEC Indeterminate 406 Reference: Section 3.6 408 INFO-CODE: 6 409 Purpose: DNSSEC Bogus 410 Reference: Section 3.7 412 INFO-CODE: 7 413 Purpose: Signature Expired 414 Reference: Section 3.8 416 INFO-CODE: 8 417 Purpose: Signature Not Yet Valid 418 Reference: Section 3.9 420 INFO-CODE: 9 421 Purpose: DNSKEY Missing 422 Reference: Section 3.10 424 INFO-CODE: 10 425 Purpose: RRSIGs Missing 426 Reference: Section 3.11 428 INFO-CODE: 11 429 Purpose: No Zone Key Bit Set 430 Reference: Section 3.12 432 INFO-CODE: 12 433 Purpose: NSEC Missing 434 Reference: Section 3.13 436 INFO-CODE: 13 437 Purpose: Cached Error 438 Reference: Section 3.14 440 INFO-CODE: 14 441 Purpose: Not Ready. 442 Reference: Section 3.15 444 INFO-CODE: 15 445 Purpose: Blocked 446 Reference: Section 3.16 448 INFO-CODE: 16 449 Purpose: Censored 450 Reference: Section 3.17 452 INFO-CODE: 17 453 Purpose: Filtered 454 Reference: Section 3.18 456 INFO-CODE: 18 457 Purpose: Prohibited 458 Reference: Section 3.19 460 INFO-CODE: 19 461 Purpose: Stale NXDomain Answer 462 Reference: Section 3.20 464 INFO-CODE: 20 465 Purpose: Not Authoritative 466 Reference: Section 3.21 468 INFO-CODE: 21 469 Purpose: Deprecated 470 Reference: Section 3.22 472 INFO-CODE: 22 473 Purpose: No Reachable Authority 474 Reference: Section 3.23 476 INFO-CODE: 23 477 Purpose: Network Error 478 Reference: Section 3.24 480 INFO-CODE: 24 481 Purpose: Invalid Data 482 Reference: Section 3.25 484 5. Security Considerations 486 Though DNSSEC continues to be deployed, unfortunately a significant 487 number of clients (~11% according to [GeoffValidation]) that receive 488 a SERVFAIL from a validating resolver because of a DNSSEC validaion 489 issue will simply ask the next (potentially non-validating) resolver 490 in their list, and thus don't get any of the protections which DNSSEC 491 should provide. 493 This information is unauthenticated information, and an attacker (e.g 494 a MITM or malicious recursive server) could insert an extended error 495 response into already untrusted data -- ideally clients and resolvers 496 would not trust any unauthenticated information, but until we live in 497 an era where all DNS answers are authenticated via DNSSEC or other 498 mechanisms [RFC2845] [RFC8094], there are some tradeoffs. As an 499 example, an attacker who is able to insert the DNSSEC Bogus Extended 500 Error into a packet could instead simply reply with a fictitious 501 address (A or AAAA) record. Note that DNS Response Codes also 502 contain no authentication and can be just as easily manipulated. 504 6. Acknowledgements 506 The authors wish to thank Joe Abley, Mark Andrews, Vittorio Bertola, 507 Stephane Bortzmeyer, Vladimir Cunat, Ralph Dolmans, Peter DeVries, 508 Peter van Dijk, Mats Dufberg, Donald Eastlake, Bob Harold, Paul 509 Hoffman, Geoff Huston, Shane Kerr, Edward Lewis, Carlos M. Martinez, 510 George Michelson, Eric Orth, Michael Sheldon, Puneet Sood, Petr 511 Spacek, Ondrej Sury, John Todd, Loganaden Velvindron, and Paul Vixie. 512 They also vaguely remember discussing this with a number of people 513 over the years, but have forgotten who all they were -- if you were 514 one of them, and are not listed, please let us know and we'll 515 acknowledge you. 517 One author also wants to thank the band "Infected Mushroom" for 518 providing a good background soundtrack (and to see if he can get away 519 with this in an RFC!) Another author would like to thank the band 520 "Mushroom Infectors". This was funny at the time we wrote it, but we 521 cannot remember why... 523 7. References 525 7.1. Normative References 527 [I-D.ietf-dnsop-serve-stale] 528 Lawrence, D., Kumari, W., and P. Sood, "Serving Stale Data 529 to Improve DNS Resiliency", draft-ietf-dnsop-serve- 530 stale-08 (work in progress), September 2019. 532 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 533 Requirement Levels", BCP 14, RFC 2119, 534 DOI 10.17487/RFC2119, March 1997, . 537 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 538 IANA Considerations Section in RFCs", RFC 2434, 539 DOI 10.17487/RFC2434, October 1998, . 542 [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", 543 RFC 2671, DOI 10.17487/RFC2671, August 1999, 544 . 546 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 547 Rose, "Protocol Modifications for the DNS Security 548 Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, 549 . 551 [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms 552 for DNS (EDNS(0))", STD 75, RFC 6891, 553 DOI 10.17487/RFC6891, April 2013, . 556 7.2. Informative References 558 [GeoffValidation] 559 IANA, "A quick review of DNSSEC Validation in today's 560 Internet", June 2016, . 563 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 564 Wellington, "Secret Key Transaction Authentication for DNS 565 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 566 . 568 [RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram 569 Transport Layer Security (DTLS)", RFC 8094, 570 DOI 10.17487/RFC8094, February 2017, . 573 Authors' Addresses 575 Warren Kumari 576 Google 577 1600 Amphitheatre Parkway 578 Mountain View, CA 94043 579 US 581 Email: warren@kumari.net 583 Evan Hunt 584 ISC 585 950 Charter St 586 Redwood City, CA 94063 587 US 589 Email: each@isc.org 591 Roy Arends 592 ICANN 594 Email: roy.arends@icann.org 596 Wes Hardaker 597 USC/ISI 598 P.O. Box 382 599 Davis, CA 95617 600 US 602 Email: ietf@hardakers.net 604 David C Lawrence 605 Oracle + Dyn 606 150 Dow St 607 Manchester, NH 03101 608 US 610 Email: tale@dd.org