draft-ietf-dnsop-extended-error-09.txt   draft-ietf-dnsop-extended-error-10.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: March 13, 2020 ISC Expires: March 30, 2020 ISC
R. Arends R. Arends
ICANN ICANN
W. Hardaker W. Hardaker
USC/ISI USC/ISI
D. Lawrence D. Lawrence
Oracle + Dyn Oracle + Dyn
September 10, 2019 September 27, 2019
Extended DNS Errors Extended DNS Errors
draft-ietf-dnsop-extended-error-09 draft-ietf-dnsop-extended-error-10
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. Though created primarily information about the cause of DNS errors. Though created primarily
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, the Extended DNS Errors option defined in of DNS and DNSSEC failures, the Extended DNS Errors option defined in
this document allows all response types to contain extended error this document allows all response types to contain extended error
information. information. Extended DNS Error information does not change the
processing of RCODEs.
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 http://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 March 13, 2020. This Internet-Draft will expire on March 30, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 24 skipping to change at page 2, line 24
Table of Contents Table of Contents
1. Introduction and background . . . . . . . . . . . . . . . . . 3 1. Introduction and background . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 4 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 4
2. Extended Error EDNS0 option format . . . . . . . . . . . . . 4 2. Extended Error EDNS0 option format . . . . . . . . . . . . . 4
3. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5 3. Defined Extended DNS Errors . . . . . . . . . . . . . . . . . 5
3.1. Extended DNS Error Code 0 - Other . . . . . . . . . . . . 5 3.1. Extended DNS Error Code 0 - Other . . . . . . . . . . . . 5
3.2. Extended DNS Error Code 1 - 3.2. Extended DNS Error Code 1 -
Unsupported DNSKEY Algorithm . . . . . . . . . . . . . . 5 Unsupported DNSKEY Algorithm . . . . . . . . . . . . . . 5
3.3. Extended DNS Error Code 2 - Unsupported 3.3. Extended DNS Error Code 2 - Unsupported DS
DS Algorithm . . . . . . . . . . . . . . . . . . . . . . 5 Digest Type . . . . . . . . . . . . . . . . . . . . . . . 5
3.4. Extended DNS Error Code 3 - Stale Answer . . . . . . . . 5 3.4. Extended DNS Error Code 3 - Stale Answer . . . . . . . . 5
3.5. Extended DNS Error Code 4 - Forged Answer . . . . . . . . 5 3.5. Extended DNS Error Code 4 - Forged Answer . . . . . . . . 5
3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate . . . . 5 3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate . . . . 6
3.7. Extended DNS Error Code 6 - DNSSEC Bogus . . . . . . . . 6 3.7. Extended DNS Error Code 6 - DNSSEC Bogus . . . . . . . . 6
3.8. Extended DNS Error Code 7 - Signature Expired . . . . . . 6 3.8. Extended DNS Error Code 7 - Signature Expired . . . . . . 6
3.9. Extended DNS Error Code 8 - Signature Not Yet Valid . . . 6 3.9. Extended DNS Error Code 8 - Signature Not Yet Valid . . . 6
3.10. Extended DNS Error Code 9 - DNSKEY Missing . . . . . . . 6 3.10. Extended DNS Error Code 9 - DNSKEY Missing . . . . . . . 6
3.11. Extended DNS Error Code 10 - RRSIGs Missing . . . . . . . 6 3.11. Extended DNS Error Code 10 - RRSIGs Missing . . . . . . . 6
3.12. Extended DNS Error Code 11 - No Zone Key Bit Set . . . . 6 3.12. Extended DNS Error Code 11 - No Zone Key Bit Set . . . . 6
3.13. Extended DNS Error Code 12 - NSEC Missing . . . . . . . . 6 3.13. Extended DNS Error Code 12 - NSEC Missing . . . . . . . . 6
3.14. Extended DNS Error Code 13 - Cached Error . . . . . . . . 6 3.14. Extended DNS Error Code 13 - Cached Error . . . . . . . . 6
3.15. Extended DNS Error Code 14 - Not Ready . . . . . . . . . 6 3.15. Extended DNS Error Code 14 - Not Ready . . . . . . . . . 7
3.16. Extended DNS Error Code 15 - Blocked . . . . . . . . . . 7 3.16. Extended DNS Error Code 15 - Blocked . . . . . . . . . . 7
3.17. Extended DNS Error Code 16 - Censored . . . . . . . . . . 7 3.17. Extended DNS Error Code 16 - Censored . . . . . . . . . . 7
3.18. Extended DNS Error Code 17 - Prohibited . . . . . . . . . 7 3.18. Extended DNS Error Code 17 - Filtered . . . . . . . . . . 7
3.19. Extended DNS Error Code 18 - Filtered . . . . . . . . . . 7 3.19. Extended DNS Error Code 17 - Prohibited . . . . . . . . . 7
3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer . . . 7 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer . . . 7
3.21. Extended DNS Error Code 20 - Lame . . . . . . . . . . . . 7 3.21. Extended DNS Error Code 20 - Not Authoritative . . . . . 7
3.22. Extended DNS Error Code 21 - Deprecated . . . . . . . . . 8 3.22. Extended DNS Error Code 21 - Deprecated . . . . . . . . . 8
3.23. Extended DNS Error Code 22 - No Reachable Authority . . . 8 3.23. Extended DNS Error Code 22 - No Reachable Authority . . . 8
3.24. Extended DNS Error Code 23 - Network Error . . . . . . . 8 3.24. Extended DNS Error Code 23 - Network Error . . . . . . . 8
3.25. Extended DNS Error Code 24 - Invalid Data . . . . . . . . 8
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
4.1. A New Extended DNS Error Code EDNS Option . . . . . . . . 8 4.1. A New Extended DNS Error Code EDNS Option . . . . . . . . 8
4.2. New Registry Table for Extended DNS Error Codes . . . . . 8 4.2. New Registry Table for Extended DNS Error Codes . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . 11 7.1. Normative References . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
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. was the answer marked REFUSED because of a lame delegation, or - e.g. was the answer marked REFUSED because of a lame delegation, or
skipping to change at page 3, line 40 skipping to change at page 3, line 41
resolver is not a validating resolver, and the user is returned a resolver is not a validating resolver, and the user is returned a
potentially harmful result. With an Extended DNS Error (EDE) option potentially harmful result. With an Extended DNS Error (EDE) option
enclosed in the response message, the resolver is able to return a enclosed in the response message, the resolver is able to return a
more descriptive reason as to why any failures happened, or add more descriptive reason as to why any failures happened, or add
additional context to a message containing a NOERROR RCODE. additional context to a message containing a NOERROR RCODE.
This document specifies a mechanism to extend DNS errors to provide This document specifies a mechanism to extend DNS errors to provide
additional information about the cause of an error. These extended additional information about the cause of an error. These extended
DNS error codes described in this document and can be used by any DNS error codes described in this document and can be used by any
system that sends DNS queries and receives a response containing an system that sends DNS queries and receives a response containing an
EDE option.. Different codes are useful in different circumstances, EDE option. Different codes are useful in different circumstances,
and thus different systems (stub resolvers, recursive resolvers, and and thus different systems (stub resolvers, recursive resolvers, and
authoritative resolvers) might receive and use them. authoritative resolvers) might receive and use them.
This document does not allow or prohibit any particular extended This document does not allow or prohibit any particular extended
error codes and information be matched with any particular RCODEs. error codes and information to be matched with any particular RCODEs.
Some combinations of extended error codes and RCODEs may seem Some combinations of extended error codes and RCODEs may seem
nonsensical (such as resolver-specific extended error codes in nonsensical (such as resolver-specific extended error codes in
responses from authoritative servers), so systems interpreting the responses from authoritative servers), so systems interpreting the
extended error codes MUST NOT assume that a combination will make extended error codes MUST NOT assume that a combination will make
sense. Receivers MUST be able to accept EDE codes and EXTRA-TEXT in sense. Receivers MUST be able to accept EDE codes and EXTRA-TEXT in
all messages, including even those with a NOERROR RCODE. all messages, including those with a NOERROR RCODE. Receivers MUST
NOT change the processing of RCODEs in messages based on extended
error codes.
1.1. Requirements notation 1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Extended Error EDNS0 option format 2. Extended Error EDNS0 option format
This draft uses an EDNS0 ([RFC2671]) option to include Extended DNS This draft uses an EDNS0 ([RFC2671]) option to include Extended DNS
skipping to change at page 4, line 40 skipping to change at page 4, line 43
o OPTION-CODE, 2 octets (defined in [RFC6891]]), for EDE is TBD. o OPTION-CODE, 2 octets (defined in [RFC6891]]), for EDE is TBD.
[RFC Editor: change TBD to the proper code once assigned by IANA.] [RFC Editor: change TBD to the proper code once assigned by IANA.]
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 plus the length of the EXTRA-TEXT section (which and should be 4 plus the length of the EXTRA-TEXT section (which
may be a zero-length string). may be a zero-length string).
o INFO-CODE, 16-bits, which is the principal contribution of this o INFO-CODE, 16-bits, which is the principal contribution of this
document. This 16-bit value, encoded in network (MSB) byte order, document. This 16-bit value, encoded in network (MSB) byte order,
provides the additional context for the RESPONSE-CODE of the DNS provides the additional context for the RESPONSE-CODE of the DNS
message. The INFO-CODE serves as an index to the "Extended DNS message. The INFO-CODE serves as an index into the "Extended DNS
Errors" registry Section 4.1. Errors" registry Section 4.1.
o EXTRA-TEXT, a variable length, UTF-8 encoded, text field that may o EXTRA-TEXT, a variable length, UTF-8 encoded, text field that may
hold additional textual information. Note: EXTRA-TEXT may be zero hold additional textual information. Note: EXTRA-TEXT may be zero
octets in length, indicating there is no EXTRA-TEXT included. octets in length, indicating there is no EXTRA-TEXT included.
Care should be take not to leak private information that an Care should be taken not to leak private information that an
observer would not otherwise have access to, such as account observer would not otherwise have access to, such as account
numbers. numbers.
The Extended DNS Error (EDE) option can be included in any response The Extended DNS Error (EDE) option can be included in any response
(SERVFAIL, NXDOMAIN, REFUSED, and even NOERROR, etc) to a query that (SERVFAIL, NXDOMAIN, REFUSED, and even NOERROR, etc) to a query that
includes OPT Pseudo-RR [RFC6891]. This document includes a set of includes OPT Pseudo-RR [RFC6891]. 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 and information codes to be defined in the future. additional error and information codes to be defined in the future.
skipping to change at page 5, line 25 skipping to change at page 5, line 30
3.1. Extended DNS Error Code 0 - Other 3.1. Extended DNS Error Code 0 - Other
The error in question falls into a category that does not match known The error in question falls into a category that does not match known
extended error codes. Implementations SHOULD include a EXTRA-TEXT extended error codes. Implementations SHOULD include a EXTRA-TEXT
value to augment this error code with additional information. value to augment this error code with additional information.
3.2. Extended DNS Error Code 1 - Unsupported DNSKEY Algorithm 3.2. Extended DNS Error Code 1 - Unsupported DNSKEY Algorithm
The resolver attempted to perform DNSSEC validation, but a DNSKEY The resolver attempted to perform DNSSEC validation, but a DNSKEY
RRSET contained only unknown algorithms. RRSET contained only unsupported DNSSEC algorithms.
3.3. Extended DNS Error Code 2 - Unsupported DS Algorithm 3.3. Extended DNS Error Code 2 - Unsupported DS Digest Type
The resolver attempted to perform DNSSEC validation, but a DS RRSET The resolver attempted to perform DNSSEC validation, but a DS RRSET
contained only unknown algorithms. contained only unsupported Digest Types.
3.4. Extended DNS Error Code 3 - Stale Answer 3.4. Extended DNS Error Code 3 - Stale Answer
The resolver was unable to resolve answer within its time limits and The resolver was unable to resolve answer within its time limits and
decided to answer with previously cached data instead of answering decided to answer with previously cached data instead of answering
with an error. This is typically caused by problems communicating with an error. This is typically caused by problems communicating
with an authoritative serever, possibly as result of a DoS attack with an authoritative serever, possibly as result of a DoS attack
against another network. against another network.
3.5. Extended DNS Error Code 4 - Forged Answer 3.5. Extended DNS Error Code 4 - Forged Answer
For policy reasons (legal obligation, or malware filtering, for For policy reasons (legal obligation, or malware filtering, for
instance), an answer was forged. instance), an answer was forged. Note that this should be used when
an answer is still provided, not when failure codes are returned
instead. See Blocked(15), Censored (16), and Filtered (17) for use
when returning other response codes.
3.6. Extended DNS Error Code 5 - DNSSEC Indeterminate 3.6. Extended DNS Error Code 5 - 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 [RFC4035].
3.7. Extended DNS Error Code 6 - DNSSEC Bogus 3.7. Extended DNS Error Code 6 - 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. ended in the Bogus state.
3.8. Extended DNS Error Code 7 - Signature Expired 3.8. Extended DNS Error Code 7 - Signature Expired
The resolver attempted to perform DNSSEC validation, but a signature The resolver attempted to perform DNSSEC validation, but all
in the validation chain was expired. signatures in an RRset in the validation chain were expired.
3.9. Extended DNS Error Code 8 - Signature Not Yet Valid 3.9. Extended DNS Error Code 8 - Signature Not Yet Valid
The resolver attempted to perform DNSSEC validation, but the The resolver attempted to perform DNSSEC validation, but all the
signatures received were not yet valid. signatures received were not yet valid.
3.10. Extended DNS Error Code 9 - DNSKEY Missing 3.10. Extended DNS Error Code 9 - DNSKEY Missing
A DS record existed at a parent, but no supported matching DNSKEY A DS record existed at a parent, but no supported matching DNSKEY
record could be found for the child. record could be found for the child.
3.11. Extended DNS Error Code 10 - RRSIGs Missing 3.11. Extended DNS Error Code 10 - RRSIGs Missing
The resolver attempted to perform DNSSEC validation, but no RRSIGs The resolver attempted to perform DNSSEC validation, but no RRSIGs
skipping to change at page 6, line 43 skipping to change at page 6, line 48
Bit was set in a DNSKEY. Bit was set in a DNSKEY.
3.13. Extended DNS Error Code 12 - NSEC Missing 3.13. Extended DNS Error Code 12 - NSEC Missing
The resolver attempted to perform DNSSEC validation, but the The resolver attempted to perform DNSSEC validation, but the
requested data was missing and a covering NSEC or NSEC3 was not requested data was missing and a covering NSEC or NSEC3 was not
provided. provided.
3.14. Extended DNS Error Code 13 - Cached Error 3.14. Extended DNS Error Code 13 - Cached Error
The resolver has cached SERVFAIL for this query. The resolver has Cached SERVFAIL for this query.
3.15. Extended DNS Error Code 14 - Not Ready 3.15. Extended DNS Error Code 14 - Not Ready
The server is unable to answer the query as it is not fully The server is unable to answer the query as it is not fully
functional (yet). functional (yet).
3.16. Extended DNS Error Code 15 - Blocked 3.16. Extended DNS Error Code 15 - Blocked
The resolver attempted to perfom a DNS query but the domain is The server is unable to respond to the request because the domain is
blacklisted due to a security policy implemented on the server being blacklisted due to an internal security policy imposed by the
directly talked to. operator of the server being directly talked to.
3.17. Extended DNS Error Code 16 - Censored 3.17. Extended DNS Error Code 16 - Censored
The resolver attempted to perfom a DNS query but the domain was The server is unable to respond to the request because the domain is
blacklisted by a security policy imposed upon the server being talked blacklisted by a security policy imposed upon the server being talked
to. Note that how the imposed policy is applied is irrelevant (in- to by an external requirement. Note that how the imposed policy is
band DNS filtering, court order, etc). applied is irrelevant (in-band DNS filtering, court order, etc).
3.18. Extended DNS Error Code 17 - Prohibited 3.18. Extended DNS Error Code 17 - Filtered
The server is unable to respond to the request because the domain is
blacklisted as requested by the client. Functionally, this amounts
to "you requested that we filter domains like this one."
3.19. Extended DNS Error Code 17 - 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, local IP addresses outside the network, blacklisted IP addresses, local
policy, etc. policy, etc.
3.19. Extended DNS Error Code 18 - Filtered
An authoritative or recursive resolver that receives a query from a
client that had requested certain domains be filtered can annotate
its REFUSED message with this code. Functionally, this amounts to
"you requested that we filter domains like this one."
3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer 3.20. Extended DNS Error Code 19 - Stale NXDOMAIN Answer
The resolver was unable to resolve an answer within its configured The resolver was unable to resolve an answer within its configured
time limits and decided to answer with a previously cached NXDOMAIN time limits and decided to answer with a previously cached NXDOMAIN
answer instead of answering with an error. This is typically caused answer instead of answering with an error. This is typically caused
by problems communicating with an authoritative serever, possibly as by problems communicating with an authoritative server, possibly as
result of a DoS attack against another network. result of a DoS attack against another network.
3.21. Extended DNS Error Code 20 - Lame 3.21. Extended DNS Error Code 20 - Not Authoritative
An authoritative server that receives a query (with the RD bit clear) An authoritative server that receives a query (with the RD bit clear,
for a domain for which it is not authoritative SHOULD include this or when not configured for recursion) for a domain for which it is
EDE code in the SERVFAIL response. A resolver that receives a query not authoritative SHOULD include this EDE code in the REFUSED
(with the RD bit clear) SHOULD include this EDE code in the REFUSED response. A resolver that receives a query (with the RD bit clear)
response. SHOULD include this EDE code in the REFUSED response.
3.22. Extended DNS Error Code 21 - Deprecated 3.22. Extended DNS Error Code 21 - Deprecated
The requested operation or query is not supported as its use has been The requested operation or query is not supported as its use has been
deprecated. deprecated.
3.23. Extended DNS Error Code 22 - No Reachable Authority 3.23. Extended DNS Error Code 22 - No Reachable Authority
The resolver could not reach any of the authoritative name servers The resolver could not reach any of the authoritative name servers
(or they refused to reply). (or they refused to reply).
3.24. Extended DNS Error Code 23 - Network Error 3.24. Extended DNS Error Code 23 - Network Error
An unrecoverable error occurred while communicating with another An unrecoverable error occurred while communicating with another
server. server.
3.25. Extended DNS Error Code 24 - Invalid Data
An authoritative server that cannot answer with data for a zone it is
otherwise configured to support. This may occur because its most
recent zone is too old, or has expired, for example.
4. IANA Considerations 4. IANA Considerations
4.1. A New Extended DNS Error Code EDNS Option 4.1. A New Extended DNS 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]
skipping to change at page 9, line 4 skipping to change at page 9, line 11
o 0 - 32767: Expert Review [RFC2434]. o 0 - 32767: Expert Review [RFC2434].
o 32768 - 49151: First come, first served. o 32768 - 49151: First come, first served.
o 49152 - 65535: Experimental / Private use. o 49152 - 65535: Experimental / Private use.
A starting set of entries, based on the contents of this document, is A starting set of entries, based on the contents of this document, is
as follows: as follows:
INFO-CODE: 0 INFO-CODE: 0
Purpose: Other Error Purpose: Other Error
Reference: Section 3.1 Reference: Section 3.1
INFO-CODE: 1 INFO-CODE: 1
Purpose: Unsupported DNSKEY Algorithm Purpose: Unsupported DNSKEY Algorithm
Reference: Section 3.2 Reference: Section 3.2
INFO-CODE: 2 INFO-CODE: 2
Purpose: Unsupported DS Algorithm Purpose: Unsupported DS Digest Type
Reference: Section 3.3 Reference: Section 3.3
INFO-CODE: 3 INFO-CODE: 3
Purpose: Stale Answer Purpose: Stale Answer
Reference: Section 3.4 Reference: Section 3.4, [I-D.ietf-dnsop-serve-stale]
INFO-CODE: 4 INFO-CODE: 4
Purpose: Forged Answer Purpose: Forged Answer
Reference: Section 3.5 Reference: Section 3.5
INFO-CODE: 5 INFO-CODE: 5
Purpose: DNSSEC Indeterminate Purpose: DNSSEC Indeterminate
Reference: Section 3.6 Reference: Section 3.6
INFO-CODE: 6 INFO-CODE: 6
skipping to change at page 10, line 21 skipping to change at page 10, line 28
INFO-CODE: 15 INFO-CODE: 15
Purpose: Blocked Purpose: Blocked
Reference: Section 3.16 Reference: Section 3.16
INFO-CODE: 16 INFO-CODE: 16
Purpose: Censored Purpose: Censored
Reference: Section 3.17 Reference: Section 3.17
INFO-CODE: 17 INFO-CODE: 17
Purpose: Prohibited Purpose: Filtered
Reference: Section 3.18 Reference: Section 3.18
INFO-CODE: 18 INFO-CODE: 18
Purpose: Filtered Purpose: Prohibited
Reference: Section 3.19 Reference: Section 3.19
INFO-CODE: 19 INFO-CODE: 19
Purpose: Stale NXDomain Answer Purpose: Stale NXDomain Answer
Reference: Section 3.20 Reference: Section 3.20
INFO-CODE: 20 INFO-CODE: 20
Purpose: Lame Purpose: Not Authoritative
Reference: Section 3.21 Reference: Section 3.21
INFO-CODE: 21 INFO-CODE: 21
Purpose: Deprecated Purpose: Deprecated
Reference: Section 3.22 Reference: Section 3.22
INFO-CODE: 22 INFO-CODE: 22
Purpose: No Reachable Authority Purpose: No Reachable Authority
Reference: Section 3.23 Reference: Section 3.23
INFO-CODE: 23 INFO-CODE: 23
Purpose: Network Error Purpose: Network Error
Reference: Section 3.24 Reference: Section 3.24
INFO-CODE: 24
Purpose: Invalid Data
Reference: Section 3.25
5. Security Considerations 5. Security Considerations
Though DNSSEC continues to be deployed, unfortunately a significant Though DNSSEC continues to be deployed, unfortunately a significant
number of clients (~11% according to [GeoffValidation]) that receive number of clients (~11% according to [GeoffValidation]) that receive
a SERVFAIL from a validating resolver because of a DNSSEC validaion a SERVFAIL from a validating resolver because of a DNSSEC validaion
issue will simply ask the next (potentially non-validating) resolver issue will simply ask the next (potentially non-validating) resolver
in their list, and thus don't get any of the protections which DNSSEC in their list, and thus don't get any of the protections which DNSSEC
should provide. should provide.
This information is unauthenticated information, and an attacker (e.g This information is unauthenticated information, and an attacker (e.g
a MITM or malicious recursive server) could insert an extended error a MITM or malicious recursive server) could insert an extended error
response into already untrusted data -- ideally clients and resolvers response into already untrusted data -- ideally clients and resolvers
would not trust any unauthenticated information, but until we live in would not trust any unauthenticated information, but until we live in
an era where all DNS answers are authenticated via DNSSEC or other an era where all DNS answers are authenticated via DNSSEC or other
mechanisms [RFC2845] [RFC8094], there are some tradeoffs. As an mechanisms [RFC2845] [RFC8094], there are some tradeoffs. As an
example, an attacker who is able to insert the DNSSEC Bogus Extended example, an attacker who is able to insert the DNSSEC Bogus Extended
Error into a packet could instead simply reply with a fictitious Error into a packet could instead simply reply with a fictitious
address (A or AAAA) record. address (A or AAAA) record. Note that DNS Response Codes also
contain no authentication and can be just as easily manipulated.
6. Acknowledgements 6. Acknowledgements
The authors wish to thank Joe Abley, Mark Andrews, Vittorio Bertola, The authors wish to thank Joe Abley, Mark Andrews, Vittorio Bertola,
Stephane Bortzmeyer, Vladimir Cunat, Ralph Dolmans, Peter DeVries, Stephane Bortzmeyer, Vladimir Cunat, Ralph Dolmans, Peter DeVries,
Peter van Dijk, Donald Eastlake, Bob Harold, Paul Hoffman, Geoff Peter van Dijk, Mats Dufberg, Donald Eastlake, Bob Harold, Paul
Huston, Shane Kerr, Edward Lewis, Carlos M. Martinez, George Hoffman, Geoff Huston, Shane Kerr, Edward Lewis, Carlos M. Martinez,
Michelson, Michael Sheldon, Puneet Sood, Petr Spacek, Ondrej Sury, George Michelson, Eric Orth, Michael Sheldon, Puneet Sood, Petr
Loganaden Velvindron, and Paul Vixie. They also vaguely remember Spacek, Ondrej Sury, John Todd, Loganaden Velvindron, and Paul Vixie.
discussing this with a number of people over the years, but have They also vaguely remember discussing this with a number of people
forgotten who all they were -- if you were one of them, and are not over the years, but have forgotten who all they were -- if you were
listed, please let us know and we'll acknowledge you. one of them, and are not listed, please let us know and we'll
acknowledge you.
One author also wants to thank the band "Infected Mushroom" for One author also wants to thank the band "Infected Mushroom" for
providing a good background soundtrack (and to see if he can get away providing a good background soundtrack (and to see if he can get away
with this in an RFC!) Another author would like to thank the band with this in an RFC!) Another author would like to thank the band
"Mushroom Infectors". This was funny at the time we wrote it, but we "Mushroom Infectors". This was funny at the time we wrote it, but we
cannot remember why... cannot remember why...
7. References 7. References
7.1. Normative References 7.1. Normative References
[I-D.ietf-dnsop-serve-stale]
Lawrence, D., Kumari, W., and P. Sood, "Serving Stale Data
to Improve DNS Resiliency", draft-ietf-dnsop-serve-
stale-08 (work in progress), September 2019.
[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, <https://www.rfc-
editor.org/info/rfc2119>. editor.org/info/rfc2119>.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 2434, IANA Considerations Section in RFCs", RFC 2434,
DOI 10.17487/RFC2434, October 1998, <https://www.rfc- DOI 10.17487/RFC2434, October 1998, <https://www.rfc-
editor.org/info/rfc2434>. editor.org/info/rfc2434>.
[RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)",
RFC 2671, DOI 10.17487/RFC2671, August 1999, RFC 2671, DOI 10.17487/RFC2671, August 1999,
<https://www.rfc-editor.org/info/rfc2671>. <https://www.rfc-editor.org/info/rfc2671>.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<https://www.rfc-editor.org/info/rfc4035>.
[RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms
for DNS (EDNS(0))", STD 75, RFC 6891, for DNS (EDNS(0))", STD 75, RFC 6891,
DOI 10.17487/RFC6891, April 2013, <https://www.rfc- DOI 10.17487/RFC6891, April 2013, <https://www.rfc-
editor.org/info/rfc6891>. editor.org/info/rfc6891>.
7.2. Informative References 7.2. 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/
 End of changes. 46 change blocks. 
63 lines changed or deleted 92 lines changed or added

This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/