< draft-ietf-dnsop-extended-error-00.txt   draft-ietf-dnsop-extended-error-01.txt >
Network Working Group W. Kumari Network Working Group W. Kumari
Internet-Draft Google Internet-Draft Google
Intended status: Standards Track E. Hunt Intended status: Standards Track E. Hunt
Expires: April 19, 2018 ISC Expires: January 3, 2019 ISC
R. Arends R. Arends
Nominet ICANN
W. Hardaker W. Hardaker
USC/ISI USC/ISI
D. Lawrence D. Lawrence
Akamai Technologies Akamai Technologies
October 16, 2017 July 02, 2018
Extended DNS Errors Extended DNS Errors
draft-ietf-dnsop-extended-error-00 draft-ietf-dnsop-extended-error-01
Abstract Abstract
This document defines an extensible method to return additional This document defines an extensible method to return additional
information about the cause of DNS errors. The primary use case is information about the cause of DNS errors. The primary use case is
to extend SERVFAIL to provide additional information about the cause to extend SERVFAIL to provide additional information about the cause
of DNS and DNSSEC failures. of DNS and DNSSEC failures.
[ Open question: The document currently defines a registry for [ Open question: The document currently defines a registry for
errors. It has also been suggested that the option also carry human errors. It has also been suggested that the option also carry human
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but could be persuaded otherwise. ] but could be persuaded otherwise. ]
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- 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 Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." 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 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. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction and background . . . . . . . . . . . . . . . . . 3 1. Introduction and background . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Extended Error EDNS0 option format . . . . . . . . . . . . . 3 2. Extended Error EDNS0 option format . . . . . . . . . . . . . 4
3. Use of the Extended DNS Error option . . . . . . . . . . . . 4 3. Use of the Extended DNS Error option . . . . . . . . . . . . 5
4. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5 4. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5
4.1. Extended DNS Error Code 100 - DNSSEC Bogus . . . . . . . 5 4.1. SERVFAIL(3) extended information codes . . . . . . . . . 6
4.2. Extended DNS Error Code 2 - DNSSEC Indeterminate . . . . 5 4.1.1. Extended DNS Error Code 1 - DNSSEC Bogus . . . . . . 6
4.3. Extended DNS Error Code 3 - Lame . . . . . . . . . . . . 5 4.1.2. Extended DNS Error Code 2 - DNSSEC Indeterminate . . 6
4.4. Extended DNS Error Code 4 - Prohibited . . . . . . . . . 5 4.1.3. Extended DNS Error Code 3 - Signature Expired . . . . 6
4.5. Extended DNS Error Code 5 - TooBusy . . . . . . . . . . . 6 4.1.4. Extended DNS Error Code 4 - Signature Not Yet Valid . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 4.1.5. Extended DNS Error Code 5 - Unsupported
6. Open questions . . . . . . . . . . . . . . . . . . . . . . . 7 DNSKEY Algorithm . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 4.1.6. Extended DNS Error Code 6 - Unsupported
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 DS Algorithm . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1.7. Extended DNS Error Code 7 - DNSKEY missing . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 8 4.1.8. Extended DNS Error Code 8 - RRSIGs missing . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 8 4.1.9. Extended DNS Error Code 9 - No Zone Key Bit Set . . . 7
Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 8 4.2. REFUSED(5) extended information codes . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 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 1. Introduction and background
There are many reasons that a DNS query may fail, some of them There are many reasons that a DNS query may fail, some of them
transient, some permanent; some can be resolved by querying another transient, some permanent; some can be resolved by querying another
server, some are likely best handled by stopping resolution. server, some are likely best handled by stopping resolution.
Unfortunately, the error signals that a DNS server can return are Unfortunately, the error signals that a DNS server can return are
very limited, and are not very expressive. This means that very limited, and are not very expressive. This means that
applications and resolvers often have to "guess" at what the issue is 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 - e.g the answer was marked REFUSED because of a lame delegation, or
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1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
0: | OPTION-CODE | 0: | OPTION-CODE |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
2: | OPTION-LENGTH | 2: | OPTION-LENGTH |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
4: | R | RESERVED | 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-CODE, 2 octets (defined in [RFC6891]), for ExtError is TBD.
o OPTION-LENGTH, 2 octets ((defined in [RFC6891]) contains the o OPTION-LENGTH, 2 octets ((defined in [RFC6891]) contains the
length of the payload (everything after OPTION-LENGTH) in octets length of the payload (everything after OPTION-LENGTH) in octets
and should be 4. and should be 4.
o RESERVED, 2 octets; the first bit (R) indicates a flag defined in o RESERVED, 2 octets; the first bit (R) indicates a flag defined in
this specification. The remaining bits are reserved for future this specification. The remaining bits are reserved for future
use, potentially as additional flags. 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. Currently the only defined flag is the R flag.
R - Retry The R (or Retry) flag provides a hint to the receiver that R - Retry The R (or Retry) flag provides a hint to the receiver that
it should retry the query, probably by querying another server. it should retry the query, probably by querying another server.
If the R bit is set (1), the sender believes that retrying the 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 query may provide a successful answer next time; if the R bit is
clear (0), the sender believes that it should not ask another clear (0), the sender believes that it should not ask another
server. server.
The remaining bits in the RESERVED field are reserved for future use 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 and MUST be set to 0 by the sender and SHOULD be ignored by the
receiver. 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 3. Use of the Extended DNS Error option
The Extended DNS Error (EDE) is an EDNS option. It can be included The Extended DNS Error (EDE) is an EDNS option. It can be included
in any error response (SERVFAIL, NXDOMAIN, REFUSED, etc) to a query in any error response (SERVFAIL, NXDOMAIN, REFUSED, etc) to a query
that includes an EDNS option. This document includes a set of that includes an EDNS option. This document includes a set of
initial codepoints (and requests to the IANA to add them to the initial codepoints (and requests to the IANA to add them to the
registry), but is extensible via the IANA registry to allow 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 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 receiver may want to do with this annotated error. The mechanism is
specifically designed to be extensible, and so implementations may specifically designed to be extensible, and so implementations may
receive EDE codes that it does not understand. The R flag allows 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 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 response with an unknown code - retry or drop the query. Note that
this flag is only a suggestion or hint. Receivers can choose to this flag is only a suggestion or hint. Receivers can choose to
ignore this hint. 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 4. Defined Extended DNS Errors
This document defines some initial EDE codes. The mechanism is This document defines some initial EDE codes. The mechanism is
intended to be extensible, and additional codepoints will be intended to be extensible, and additional codepoints will be
registered in the "Extended DNS Errors" registry. This document registered in the "Extended DNS Errors" registry. This document
provides suggestions for the R flag, but the originating server may provides suggestions for the R flag, but the originating server may
ignore these recommendations if it knows better. 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 The resolver attempted to perform DNSSEC validation, but validation
ended in the Bogus state. The R flag should not be set. 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 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 An authoritative resolver that receives a query (with the RD bit
clear) for a domain for which it is not authoritative SHOULD include clear) for a domain for which it is not authoritative SHOULD include
this EDE code in the REFUSED response. this EDE code in the REFUSED response. Implementations should set
the R flag in this case (another nameserver might not be lame).
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 An authoritative or recursive resolver that receives a query from an
"unauthorized" client can annotate its REFUSED message with this "unauthorized" client can annotate its REFUSED message with this
code. Examples of "unauthorized" clients are recursive queries from 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 Implementations SHOULD allow operators to define what to set the R
flag to in this case. 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 5. IANA Considerations
[This section under construction, beware. ] [This section under construction, beware. ]
5.1. new Extended Error Code EDNS Option
This document defines a new EDNS(0) option, entitled "Extended DNS This document defines a new EDNS(0) option, entitled "Extended DNS
Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes
(OPT)" registry [to be removed upon publication: (OPT)" registry [to be removed upon publication:
[http://www.iana.org/assignments/dns-parameters/dns- [http://www.iana.org/assignments/dns-parameters/dns-
parameters.xhtml#dns-parameters-11] parameters.xhtml#dns-parameters-11]
Value Name Status Reference Value Name Status Reference
----- ---------------- ------ ------------------ ----- ---------------- ------ ------------------
TBD Extended DNS Error TBD [ This document ] TBD Extended DNS Error TBD [ This document ]
Data Tag Name Length Meaning ---- ---- ------ ------- TBD1 FooBar N 5.2. new Extended Error Code EDNS Option
FooBar server
The IANA is requested to create and maintain the "Extended DNS Error This document defines a new double-index IANA registry table, where
codes" registry. The codepoint space is broken into 3 ranges: 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 1 - 16384: Specification required.
o 16385 - 65000: First Come First Served o 16385 - 65000: First Come First Served
o 65000 - 65534: Experimental / Private use o 65000 - 65534: Experimental / Private use
The codepoints 0, 65535 are reserved. 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 <xref target="errbogus" /> |
| SERVFAIL(2) | DNSSEC_INDETERMINATE(2) | DNSSEC Validation resulted in Indeterminate | section <xref target="errindeterminate" /> |
[incomplete]
6. Open questions 6. Open questions
1 Can this be included in *any* response or only responses to 1 Can this be included in *any* response or only responses to
requests that included an EDNS option? Resolvers are supposed to requests that included an EDNS option? Resolvers are supposed to
ignore additional. EDNS capable ones are supposed to simply ignore additional. EDNS capable ones are supposed to simply
ignore unknown options. I know the spec says you can only include 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 EDNS0 in a response if in a request -- it is time to reevaluate
this? this?
2 Can this be applied to *any* response, or only error responses? 2 Can this be applied to *any* response, or only error responses?
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9. References 9. References
9.1. Normative References 9.1. Normative References
[IANA.AS_Numbers] [IANA.AS_Numbers]
IANA, "Autonomous System (AS) Numbers", IANA, "Autonomous System (AS) Numbers",
<http://www.iana.org/assignments/as-numbers>. <http://www.iana.org/assignments/as-numbers>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, <https://www.rfc- DOI 10.17487/RFC2119, March 1997,
editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
9.2. Informative References 9.2. Informative References
[GeoffValidation] [GeoffValidation]
IANA, "A quick review of DNSSEC Validation in today's IANA, "A quick review of DNSSEC Validation in today's
Internet", June 2016, <http://www.potaroo.net/ Internet", June 2016, <http://www.potaroo.net/
presentations/2016-06-27-dnssec.pdf>. presentations/2016-06-27-dnssec.pdf>.
[I-D.ietf-sidr-iana-objects] [I-D.ietf-sidr-iana-objects]
Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects
issued by IANA", draft-ietf-sidr-iana-objects-03 (work in issued by IANA", draft-ietf-sidr-iana-objects-03 (work in
progress), May 2011. progress), May 2011.
Appendix A. Changes / Author Notes. Appendix A. Changes / Author Notes.
[RFC Editor: Please remove this section before publication ] [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: From -02 to -03:
o Added David Lawrence -- I somehow missed that in last version. o Added David Lawrence -- I somehow missed that in last version.
From -00 to -01; From -00 to -01;
o Fixed up some of the text, minor clarifications. o Fixed up some of the text, minor clarifications.
Authors' Addresses Authors' Addresses
skipping to change at page 9, line 4 skipping to change at page 10, line 42
Authors' Addresses Authors' Addresses
Warren Kumari Warren Kumari
Google Google
1600 Amphitheatre Parkway 1600 Amphitheatre Parkway
Mountain View, CA 94043 Mountain View, CA 94043
US US
Email: warren@kumari.net Email: warren@kumari.net
Evan Hunt Evan Hunt
ISC ISC
950 Charter St 950 Charter St
Redwood City, CA 94063 Redwood City, CA 94063
US US
Email: each@isc.org Email: each@isc.org
Roy Arends Roy Arends
Nominet ICANN
UK
Email: TBD Email: roy.arends@icann.org
Wes Hardaker Wes Hardaker
USC/ISI USC/ISI
P.O. Box 382 P.O. Box 382
Davis, VA 95617 Davis, VA 95617
US US
Email: ietf@hardakers.net
David C Lawrence David C Lawrence
Akamai Technologies Akamai Technologies
150 Broadway 150 Broadway
Cambridge, MA 02142-1054 Cambridge, MA 02142-1054
US US
Email: tale@akamai.com Email: tale@akamai.com
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