--- 1/draft-ietf-dnsop-extended-error-00.txt 2018-07-02 13:19:07.817507503 -0700 +++ 2/draft-ietf-dnsop-extended-error-01.txt 2018-07-02 13:19:07.921510660 -0700 @@ -1,25 +1,25 @@ Network Working Group W. Kumari Internet-Draft Google Intended status: Standards Track E. Hunt -Expires: April 19, 2018 ISC +Expires: January 3, 2019 ISC R. Arends - Nominet + ICANN W. Hardaker USC/ISI D. Lawrence Akamai Technologies - October 16, 2017 + July 02, 2018 Extended DNS Errors - draft-ietf-dnsop-extended-error-00 + draft-ietf-dnsop-extended-error-01 Abstract This document defines an extensible method to return additional information about the cause of DNS errors. The primary use case is to extend SERVFAIL to provide additional information about the cause of DNS and DNSSEC failures. [ Open question: The document currently defines a registry for errors. It has also been suggested that the option also carry human @@ -36,65 +36,77 @@ but could be persuaded otherwise. ] Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- - Drafts is at http://datatracker.ietf.org/drafts/current/. + Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 19, 2018. + This Internet-Draft will expire on January 3, 2019. Copyright Notice - Copyright (c) 2017 IETF Trust and the persons identified as the + Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents - (http://trustee.ietf.org/license-info) in effect on the date of + (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction and background . . . . . . . . . . . . . . . . . 3 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 - 2. Extended Error EDNS0 option format . . . . . . . . . . . . . 3 - 3. Use of the Extended DNS Error option . . . . . . . . . . . . 4 + 2. Extended Error EDNS0 option format . . . . . . . . . . . . . 4 + 3. Use of the Extended DNS Error option . . . . . . . . . . . . 5 4. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5 - 4.1. Extended DNS Error Code 100 - DNSSEC Bogus . . . . . . . 5 - 4.2. Extended DNS Error Code 2 - DNSSEC Indeterminate . . . . 5 - 4.3. Extended DNS Error Code 3 - Lame . . . . . . . . . . . . 5 - 4.4. Extended DNS Error Code 4 - Prohibited . . . . . . . . . 5 - 4.5. Extended DNS Error Code 5 - TooBusy . . . . . . . . . . . 6 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 - 6. Open questions . . . . . . . . . . . . . . . . . . . . . . . 7 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 9.1. Normative References . . . . . . . . . . . . . . . . . . 8 - 9.2. Informative References . . . . . . . . . . . . . . . . . 8 - Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 8 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 + 4.1. SERVFAIL(3) extended information codes . . . . . . . . . 6 + 4.1.1. Extended DNS Error Code 1 - DNSSEC Bogus . . . . . . 6 + 4.1.2. Extended DNS Error Code 2 - DNSSEC Indeterminate . . 6 + 4.1.3. Extended DNS Error Code 3 - Signature Expired . . . . 6 + 4.1.4. Extended DNS Error Code 4 - Signature Not Yet Valid . 6 + 4.1.5. Extended DNS Error Code 5 - Unsupported + DNSKEY Algorithm . . . . . . . . . . . . . . . . . . 6 + 4.1.6. Extended DNS Error Code 6 - Unsupported + DS Algorithm . . . . . . . . . . . . . . . . . . . . 6 + 4.1.7. Extended DNS Error Code 7 - DNSKEY missing . . . . . 6 + 4.1.8. Extended DNS Error Code 8 - RRSIGs missing . . . . . 6 + 4.1.9. Extended DNS Error Code 9 - No Zone Key Bit Set . . . 7 + 4.2. REFUSED(5) extended information codes . . . . . . . . . . 7 + 4.2.1. Extended DNS Error Code 1 - Lame . . . . . . . . . . 7 + 4.2.2. Extended DNS Error Code 2 - Prohibited . . . . . . . 7 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 + 5.1. new Extended Error Code EDNS Option . . . . . . . . . . . 7 + 5.2. new Extended Error Code EDNS Option . . . . . . . . . . . 7 + 6. Open questions . . . . . . . . . . . . . . . . . . . . . . . 8 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 + 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 + 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 + 9.2. Informative References . . . . . . . . . . . . . . . . . 9 + Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 10 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction and background There are many reasons that a DNS query may fail, some of them transient, some permanent; some can be resolved by querying another server, some are likely best handled by stopping resolution. Unfortunately, the error signals that a DNS server can return are very limited, and are not very expressive. This means that applications and resolvers often have to "guess" at what the issue is - e.g the answer was marked REFUSED because of a lame delegation, or @@ -138,151 +150,211 @@ 1 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 0: | OPTION-CODE | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 2: | OPTION-LENGTH | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 4: | R | RESERVED | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ - 6: | CODE | + 6: | RESPONSE-CODE | + +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ + 8: | INFO-CODE | + +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ + A: | EXTRA-TEXT | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ o OPTION-CODE, 2 octets (defined in [RFC6891]), for ExtError is TBD. o OPTION-LENGTH, 2 octets ((defined in [RFC6891]) contains the length of the payload (everything after OPTION-LENGTH) in octets and should be 4. o RESERVED, 2 octets; the first bit (R) indicates a flag defined in this specification. The remaining bits are reserved for future use, potentially as additional flags. - o CODE, 2 octets. + o RESPONSE-CODE, 2 octets: this SHOULD be a copy of the RCODE from + the primary DNS packet. When including multiple extended error + EDNS0 records in a response in order to provide additional error + information, the RESPONSE-CODE MAY be a different RCODE. + + o INFO-CODE, 2 octets. + + o A variable length EXTRA-TEXT field holding additional textual + information. It may be zero length when no additional textual + information is included. Currently the only defined flag is the R flag. R - Retry The R (or Retry) flag provides a hint to the receiver that it should retry the query, probably by querying another server. If the R bit is set (1), the sender believes that retrying the query may provide a successful answer next time; if the R bit is clear (0), the sender believes that it should not ask another server. The remaining bits in the RESERVED field are reserved for future use and MUST be set to 0 by the sender and SHOULD be ignored by the receiver. - Code: A code point into the IANA "Extended DNS Errors" registry. + INFO-CODE: A code point that, when combined with the RCODE from the + DNS packet, serve as a joint-index into the IANA "Extended DNS + Errors" registry. 3. Use of the Extended DNS Error option The Extended DNS Error (EDE) is an EDNS option. It can be included in any error response (SERVFAIL, NXDOMAIN, REFUSED, etc) to a query that includes an EDNS option. This document includes a set of initial codepoints (and requests to the IANA to add them to the registry), but is extensible via the IANA registry to allow - additional error codes to be defined in the future. + additional error and information codes to be defined in the future. The R (Retry) flag provides a hint (or suggestion) as to what the receiver may want to do with this annotated error. The mechanism is specifically designed to be extensible, and so implementations may receive EDE codes that it does not understand. The R flag allows implementations to make a decision as to what to do if it receives a response with an unknown code - retry or drop the query. Note that this flag is only a suggestion or hint. Receivers can choose to ignore this hint. + The EXTRA-INFO textual field may be zero-length, or may hold + additional information useful to network operators. + 4. Defined Extended DNS Errors This document defines some initial EDE codes. The mechanism is intended to be extensible, and additional codepoints will be registered in the "Extended DNS Errors" registry. This document provides suggestions for the R flag, but the originating server may ignore these recommendations if it knows better. -4.1. Extended DNS Error Code 100 - DNSSEC Bogus + The RESPONSE-CODE and the INFO-CODE from the EDE EDNS option is used + to serve as a double index into the "Extended DNS Error codes" IANA + registry, the initial values for which are defined in the following + sub-sections. + +4.1. SERVFAIL(3) extended information codes + +4.1.1. Extended DNS Error Code 1 - DNSSEC Bogus The resolver attempted to perform DNSSEC validation, but validation ended in the Bogus state. The R flag should not be set. -4.2. Extended DNS Error Code 2 - DNSSEC Indeterminate +4.1.2. Extended DNS Error Code 2 - DNSSEC Indeterminate The resolver attempted to perform DNSSEC validation, but validation - ended in the Indeterminate state. + ended in the Indeterminate state. The R flag should not be set. - Usually attached to SERVFAIL messages. The R flag should not be set. +4.1.3. Extended DNS Error Code 3 - Signature Expired -4.3. Extended DNS Error Code 3 - Lame + The resolver attempted to perform DNSSEC validation, but the + signature was expired. The R flag should not be set. + +4.1.4. Extended DNS Error Code 4 - Signature Not Yet Valid + + The resolver attempted to perform DNSSEC validation, but the + signatures received were not yet valid. The R flag should not be + set. + +4.1.5. Extended DNS Error Code 5 - Unsupported DNSKEY Algorithm + + The resolver attempted to perform DNSSEC validation, but a DNSKEY + RRSET contained only unknown algorithms. The R flag should not be + set. + +4.1.6. Extended DNS Error Code 6 - Unsupported DS Algorithm + + The resolver attempted to perform DNSSEC validation, but a DS RRSET + contained only unknown algorithms. The R flag should not be set. + +4.1.7. Extended DNS Error Code 7 - DNSKEY missing + + A DS record existed at a parent, but no DNSKEY record could be found + for the child. The R flag should not be set. + +4.1.8. Extended DNS Error Code 8 - RRSIGs missing + + The resolver attempted to perform DNSSEC validation, but no RRSIGs + could be found for at least one RRset where RRSIGs were expected. + +4.1.9. Extended DNS Error Code 9 - No Zone Key Bit Set + + The resolver attempted to perform DNSSEC validation, but no Zone Key + Bit was set in a DNSKEY. + +4.2. REFUSED(5) extended information codes + +4.2.1. Extended DNS Error Code 1 - Lame An authoritative resolver that receives a query (with the RD bit clear) for a domain for which it is not authoritative SHOULD include - this EDE code in the REFUSED response. - - Implementations should set the R flag in this case (another - nameserver might not be lame). + this EDE code in the REFUSED response. Implementations should set + the R flag in this case (another nameserver might not be lame). -4.4. Extended DNS Error Code 4 - Prohibited +4.2.2. Extended DNS Error Code 2 - Prohibited An authoritative or recursive resolver that receives a query from an "unauthorized" client can annotate its REFUSED message with this code. Examples of "unauthorized" clients are recursive queries from - IP addresses outside the network, blacklisted IP addresses, etc. + IP addresses outside the network, blacklisted IP addresses, local + policy, etc. Implementations SHOULD allow operators to define what to set the R flag to in this case. -4.5. Extended DNS Error Code 5 - TooBusy - - [ Ed: This might be a bad idea. It is intended to allow servers - under a DoS (for example a random subdomain attack) to signal to - recursive clients that they are being abusive and should back off. - This may be a bad idea -- it may "complete the attack", it may be - spoofable (by anyone who could also do a MITM style attack), etc. ] - - A nameserver which is under excessive load (for example, because it - is experiencing a DoS) may annotate any answer with this code. - - It is RECOMMENDED that implementations set the R flag in this case, - but may allow operators to define what to set the R flag to. - - [ agreed: bad idea -wjh ] - 5. IANA Considerations [This section under construction, beware. ] +5.1. new Extended Error Code EDNS Option + This document defines a new EDNS(0) option, entitled "Extended DNS Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes (OPT)" registry [to be removed upon publication: [http://www.iana.org/assignments/dns-parameters/dns- parameters.xhtml#dns-parameters-11] Value Name Status Reference ----- ---------------- ------ ------------------ TBD Extended DNS Error TBD [ This document ] - Data Tag Name Length Meaning ---- ---- ------ ------- TBD1 FooBar N - FooBar server +5.2. new Extended Error Code EDNS Option - The IANA is requested to create and maintain the "Extended DNS Error - codes" registry. The codepoint space is broken into 3 ranges: + This document defines a new double-index IANA registry table, where + the first index value is the RCODE value and the second index value + is the INFO-CODE from the Extended DNS Error EDNS option defined in + this document. The IANA is requested to create and maintain this + "Extended DNS Error codes" registry. The codepoint space for each + RCODE index is to be broken into 3 ranges: o 1 - 16384: Specification required. o 16385 - 65000: First Come First Served o 65000 - 65534: Experimental / Private use The codepoints 0, 65535 are reserved. + A starting table, based on the contents of this document, is as + follows: + +| RCODE | EDE-INFO-CODE | Meaning | Ref | +|-------------+-------------------------+---------------------------------------------+------------------------------------------| +| SERVFAIL(2) | DNSSEC_BOGUS(1) | DNSSEC Validation resulted in Bogus | section | +| SERVFAIL(2) | DNSSEC_INDETERMINATE(2) | DNSSEC Validation resulted in Indeterminate | section | + +[incomplete] + 6. Open questions 1 Can this be included in *any* response or only responses to requests that included an EDNS option? Resolvers are supposed to ignore additional. EDNS capable ones are supposed to simply ignore unknown options. I know the spec says you can only include EDNS0 in a response if in a request -- it is time to reevaluate this? 2 Can this be applied to *any* response, or only error responses? @@ -323,39 +395,55 @@ 9. References 9.1. Normative References [IANA.AS_Numbers] IANA, "Autonomous System (AS) Numbers", . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, - DOI 10.17487/RFC2119, March 1997, . + DOI 10.17487/RFC2119, March 1997, + . 9.2. Informative References [GeoffValidation] IANA, "A quick review of DNSSEC Validation in today's Internet", June 2016, . [I-D.ietf-sidr-iana-objects] Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects issued by IANA", draft-ietf-sidr-iana-objects-03 (work in progress), May 2011. Appendix A. Changes / Author Notes. [RFC Editor: Please remove this section before publication ] + From -00 to -01: + + o Address comments from IETF meeting. + + o document copying the response code + + o mention zero length fields are ok + + o clarify lookup procedure + + o mention that table isn't done + + From -03 to -IETF 00: + + o Renamed to draft-ietf-dnsop-extended-error + From -02 to -03: o Added David Lawrence -- I somehow missed that in last version. From -00 to -01; o Fixed up some of the text, minor clarifications. Authors' Addresses @@ -359,37 +447,38 @@ Authors' Addresses Warren Kumari Google 1600 Amphitheatre Parkway Mountain View, CA 94043 US Email: warren@kumari.net + Evan Hunt ISC 950 Charter St Redwood City, CA 94063 US Email: each@isc.org - Roy Arends - Nominet - UK + ICANN - Email: TBD + Email: roy.arends@icann.org Wes Hardaker USC/ISI P.O. Box 382 Davis, VA 95617 US + Email: ietf@hardakers.net + David C Lawrence Akamai Technologies 150 Broadway Cambridge, MA 02142-1054 US Email: tale@akamai.com