draft-ietf-dnsop-no-response-issue-09.txt   draft-ietf-dnsop-no-response-issue-10.txt 
Network Working Group M. Andrews Network Working Group M. Andrews
Internet-Draft ISC Internet-Draft R. Bellis
Intended status: Best Current Practice July 18, 2018 Intended status: Best Current Practice ISC
Expires: January 19, 2019 Expires: January 21, 2019 July 20, 2018
A Common Operational Problem in DNS Servers - Failure To Respond. A Common Operational Problem in DNS Servers - Failure To Respond.
draft-ietf-dnsop-no-response-issue-09 draft-ietf-dnsop-no-response-issue-10
Abstract Abstract
The DNS is a query / response protocol. Failing to respond to The DNS is a query / response protocol. Failing to respond to
queries, or responding incorrectly, causes both immediate operational queries, or responding incorrectly, causes both immediate operational
problems and long term problems with protocol development. problems and long term problems with protocol development.
This document identifies a number of common kinds of queries to which This document identifies a number of common kinds of queries to which
some servers either fail to respond or else respond incorrectly. some servers either fail to respond or else respond incorrectly.
This document also suggests procedures for TLD and other zone This document also suggests procedures for TLD and other zone
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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 https://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 January 19, 2019. This Internet-Draft will expire on January 21, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 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.
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
(https://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 publication of this document. Please review these documents
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3.2.2. EDNS Queries - Version Specific . . . . . . . . . . . 7 3.2.2. EDNS Queries - Version Specific . . . . . . . . . . . 7
3.2.3. EDNS Options . . . . . . . . . . . . . . . . . . . . 7 3.2.3. EDNS Options . . . . . . . . . . . . . . . . . . . . 7
3.2.4. EDNS Flags . . . . . . . . . . . . . . . . . . . . . 7 3.2.4. EDNS Flags . . . . . . . . . . . . . . . . . . . . . 7
3.2.5. Truncated EDNS Responses . . . . . . . . . . . . . . 8 3.2.5. Truncated EDNS Responses . . . . . . . . . . . . . . 8
3.2.6. DO Bit Handling . . . . . . . . . . . . . . . . . . . 8 3.2.6. DO Bit Handling . . . . . . . . . . . . . . . . . . . 8
3.2.7. EDNS over TCP . . . . . . . . . . . . . . . . . . . . 8 3.2.7. EDNS over TCP . . . . . . . . . . . . . . . . . . . . 8
4. Firewalls and Load Balancers . . . . . . . . . . . . . . . . 8 4. Firewalls and Load Balancers . . . . . . . . . . . . . . . . 8
5. Scrubbing Services . . . . . . . . . . . . . . . . . . . . . 9 5. Scrubbing Services . . . . . . . . . . . . . . . . . . . . . 9
6. Whole Answer Caches . . . . . . . . . . . . . . . . . . . . . 10 6. Whole Answer Caches . . . . . . . . . . . . . . . . . . . . . 10
7. Response Code Selection . . . . . . . . . . . . . . . . . . . 10 7. Response Code Selection . . . . . . . . . . . . . . . . . . . 10
8. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Testing - Basic DNS . . . . . . . . . . . . . . . . . . . 11 8.1. Testing - Basic DNS . . . . . . . . . . . . . . . . . . . 11
8.1.1. Is The Server Configured For The Zone? . . . . . . . 11 8.1.1. Is The Server Configured For The Zone? . . . . . . . 11
8.1.2. Testing Unknown Types . . . . . . . . . . . . . . . . 12 8.1.2. Testing Unknown Types . . . . . . . . . . . . . . . . 11
8.1.3. Testing Header Bits . . . . . . . . . . . . . . . . . 12 8.1.3. Testing Header Bits . . . . . . . . . . . . . . . . . 12
8.1.4. Testing Unknown Opcodes . . . . . . . . . . . . . . . 14 8.1.4. Testing Unknown Opcodes . . . . . . . . . . . . . . . 13
8.1.5. Testing Recursive Queries . . . . . . . . . . . . . . 15 8.1.5. Testing Recursive Queries . . . . . . . . . . . . . . 14
8.1.6. Testing TCP . . . . . . . . . . . . . . . . . . . . . 15 8.1.6. Testing TCP . . . . . . . . . . . . . . . . . . . . . 14
8.2. Testing - Extended DNS . . . . . . . . . . . . . . . . . 16 8.2. Testing - Extended DNS . . . . . . . . . . . . . . . . . 15
8.2.1. Testing Minimal EDNS . . . . . . . . . . . . . . . . 16 8.2.1. Testing Minimal EDNS . . . . . . . . . . . . . . . . 15
8.2.2. Testing EDNS Version Negotiation . . . . . . . . . . 16 8.2.2. Testing EDNS Version Negotiation . . . . . . . . . . 16
8.2.3. Testing Unknown EDNS Options . . . . . . . . . . . . 17 8.2.3. Testing Unknown EDNS Options . . . . . . . . . . . . 16
8.2.4. Testing Unknown EDNS Flags . . . . . . . . . . . . . 18 8.2.4. Testing Unknown EDNS Flags . . . . . . . . . . . . . 17
8.2.5. Testing EDNS Version Negotiation With Unknown EDNS 8.2.5. Testing EDNS Version Negotiation With Unknown EDNS
Flags . . . . . . . . . . . . . . . . . . . . . . . . 18 Flags . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2.6. Testing EDNS Version Negotiation With Unknown EDNS 8.2.6. Testing EDNS Version Negotiation With Unknown EDNS
Options . . . . . . . . . . . . . . . . . . . . . . . 19 Options . . . . . . . . . . . . . . . . . . . . . . . 18
8.2.7. Testing Truncated Responses . . . . . . . . . . . . . 20 8.2.7. Testing Truncated Responses . . . . . . . . . . . . . 19
8.2.8. Testing DNSSEC Queries . . . . . . . . . . . . . . . 20 8.2.8. Testing DNSSEC Queries . . . . . . . . . . . . . . . 19
8.2.9. Testing EDNS Version Negotiation With DNSSEC . . . . 21 8.2.9. Testing EDNS Version Negotiation With DNSSEC . . . . 20
8.2.10. Testing With Multiple Defined EDNS Options . . . . . 22 8.2.10. Testing With Multiple Defined EDNS Options . . . . . 21
8.3. When EDNS Is Not Supported . . . . . . . . . . . . . . . 22 8.3. When EDNS Is Not Supported . . . . . . . . . . . . . . . 21
9. Remediation . . . . . . . . . . . . . . . . . . . . . . . . . 22 9. Remediation . . . . . . . . . . . . . . . . . . . . . . . . . 22
10. Security Considerations . . . . . . . . . . . . . . . . . . . 24 10. Security Considerations . . . . . . . . . . . . . . . . . . . 23
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
12.1. Normative References . . . . . . . . . . . . . . . . . . 24 12.1. Normative References . . . . . . . . . . . . . . . . . . 23
12.2. Informative References . . . . . . . . . . . . . . . . . 25 12.2. Informative References . . . . . . . . . . . . . . . . . 24
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction 1. Introduction
The DNS [RFC1034], [RFC1035] is a query / response protocol. Failing The DNS [RFC1034], [RFC1035] is a query / response protocol. Failing
to respond to queries, or responding incorrectly, causes both to respond to queries, or responding incorrectly, causes both
immediate operational problems and long term problems with protocol immediate operational problems and long term problems with protocol
development. development.
Failure to respond to a query is indistinguishable from packet loss Failure to respond to a query is indistinguishable from packet loss
without doing an analysis of query-response patterns. Additionally without doing an analysis of query-response patterns. Additionally
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They are: EDNS queries with and without extensions; queries for They are: EDNS queries with and without extensions; queries for
unknown (unallocated) or unsupported types; and filtering of TCP unknown (unallocated) or unsupported types; and filtering of TCP
queries. queries.
3.1. Basic DNS Queries 3.1. Basic DNS Queries
3.1.1. Zone Existence 3.1.1. Zone Existence
Initially, to test existence of the zone, an SOA query should be Initially, to test existence of the zone, an SOA query should be
made. If the SOA record is not returned but some other response is made. If the SOA record is not returned but some other response is
returned, this is a indication of a bad delegation. If the tester returned, this is an indication of a bad delegation.
fails to get a response to a SOA query, the Operator should make an A
query for the zone, as some nameservers fail to respond to SOA
queries but will respond to A queries.
3.1.2. Unknown / Unsupported Type Queries 3.1.2. Unknown / Unsupported Type Queries
Identifying servers that fail to respond to unknown or unsupported Identifying servers that fail to respond to unknown or unsupported
types can be done by making an initial DNS query for an A record, types can be done by making an initial DNS query for an A record,
making a number of queries for an unallocated type, then making a making a number of queries for an unallocated type, then making a
query for an A record again. IANA maintains a registry of allocated query for an A record again. IANA maintains a registry of allocated
types. types.
If the server responds to the first and last queries but fails to If the server responds to the first and last queries but fails to
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Scrubbing services, unlike firewalls, are also turned on and off in Scrubbing services, unlike firewalls, are also turned on and off in
response to denial of service attacks. One needs to take care when response to denial of service attacks. One needs to take care when
choosing a scrubbing service. choosing a scrubbing service.
Ideally, Operators should run these tests against a scrubbing service Ideally, Operators should run these tests against a scrubbing service
to ensure that these tests are not seen as attack vectors. to ensure that these tests are not seen as attack vectors.
6. Whole Answer Caches 6. Whole Answer Caches
Whole answer caches take a previously constructed answer and return Whole answer caches take a previously constructed answer and return
it to a subsequent query for the same qname, qtype and qclass, just it to a subsequent query for the same question. However, they can
updating the query id field and possibly the qname to match the return the wrong response if they do not take all of the relevant
incoming query to avoid constructing each response individually. attributes of the query into account.
Whole answer caches can return the wrong response to a query if they
do not take all of the attributes of the query into account, rather
than just some of them e.g. qname, qtype and qclass. This has
implications when testing and with overall protocol compliance.
Two current examples are:
o Whole answer caches that ignore the EDNS version field which
results in incorrect answers to non EDNS version 0 queries being
returned if they were preceded by a EDNS version 0 query for the
same name and type.
o Whole answer caches that ignore the EDNS options in the query In addition to the standard tuple of <qname,qtype,qclass> a non-
resulting in options only working some of the time and/or options exhaustive set of attributes that must be considered include: RD, AD,
being returned when not requested. CD, OPT record, DO, EDNS buffer size, EDNS version, EDNS options, and
transport.
7. Response Code Selection 7. Response Code Selection
Choosing the correct response code when responding to DNS queries is Choosing the correct response code when responding to DNS queries is
important. Just because a DNS qtype is not implemented does not mean important. Response codes should be chosen considering how clients
that NOTIMP is the correct response code to return. Response codes will handle them.
should be chosen considering how clients will handle them.
For unimplemented opcodes NOTIMP is the expected response code. For For unimplemented opcodes NOTIMP is the expected response code. For
example, a new opcode could change the message format by extending example, a new opcode could change the message format by extending
the header or changing the structure of the records etc. This may the header or changing the structure of the records etc.
result in FORMERR being returned though NOTIMP would be more correct.
Unimplemented type codes, Name Error (NXDOMAIN) and NOERROR (no data) For unimplemented type codes, and in the absence of other errors, the
are the expected response codes. A server is not supposed to serve a only valid response is NoError if the qname exists, and NameError
zone which contains unsupported types ([RFC1034]) so the only thing (NXDOMAIN) otherwise. For Meta-RRs NOTIMP may be returned
left is return if the QNAME exists or not. NOTIMP and REFUSED are instead.&#8232;
not useful responses as they force the clients to try the other
authoritative servers for a zone looking for a server which will
answer the query.
Meta queries may be the exception but these need to be thought about If a zone cannot be loaded because it contains unimplemented type
on a case by case basis. codes that are not encoded as unknown record types according to
[RFC3597] then the expected response is SERVFAIL.
If the server supports EDNS and receives a query with an unsupported If the server supports EDNS and receives a query with an unsupported
EDNS version, the correct response is BADVERS [RFC6891]. EDNS version, the correct response is BADVERS [RFC6891].
If the server does not support EDNS at all, FORMERR and NOTIMP are If the server does not support EDNS at all, FORMERR and NOTIMP are
the expected error codes. That said a minimal EDNS server the expected error codes. That said a minimal EDNS server
implementation requires parsing the OPT records and responding with implementation requires parsing the OPT records and responding with
an empty OPT record. There is no need to interpret any EDNS options an empty OPT record. There is no need to interpret any EDNS options
present in the request as unsupported EDNS options are expected to be present in the request as unsupported EDNS options are expected to be
ignored [RFC6891]. ignored [RFC6891].
8. Testing 8. Testing
Testing is divided into two sections. Basic DNS which all servers Testing is divided into two sections. "Basic DNS", which all servers
should meet and Extended DNS which should be met by all servers that should meet, and "Extended DNS", which should be met by all servers
support EDNS (a server is deemed to support EDNS if it gives a valid that support EDNS (a server is deemed to support EDNS if it gives a
EDNS response to any EDNS query). If a server does not support EDNS valid EDNS response to any EDNS query). If a server does not support
it should still respond to all the tests. EDNS it should still respond to all the tests.
It is advisable to run all of the tests below in parallel so as to It is advisable to run all of the tests below in parallel so as to
minimise the delays due to multiple timeouts when the servers do not minimise the delays due to multiple timeouts when the servers do not
respond. There are 16 queries directed to each nameserver assuming respond. There are 16 queries directed to each nameserver (assuming
no packet loss testing different aspects of Basic DNS and EDNS. no packet loss) testing different aspects of Basic DNS and Extended
DNS.
The tests below use dig from BIND 9.11.0. The tests below use dig from BIND 9.11.0.
8.1. Testing - Basic DNS 8.1. Testing - Basic DNS
This first set of tests cover basic DNS server behaviour and all This first set of tests cover basic DNS server behaviour and all
servers should pass these tests. servers should pass these tests.
8.1.1. Is The Server Configured For The Zone? 8.1.1. Is The Server Configured For The Zone?
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set and without to serve. This query is made with no DNS flag bits set and without
EDNS. EDNS.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We do not expect set in the response, RA may also be set [RFC1034]. We do not expect
a OPT record to be returned [RFC6891]. an OPT record to be returned [RFC6891].
Verify the server is configured for the zone: Verify the server is configured for the zone:
dig +noedns +noad +norec soa $zone @$server dig +noedns +noad +norec soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
8.1.2. Testing Unknown Types 8.1.2. Testing Unknown Types
Ask for the TYPE1000 record at the zone's name. This query is made Ask for the TYPE1000 record at the zone's name. This query is made
with no DNS flag bits set and without EDNS. TYPE1000 has been chosen with no DNS flag bits set and without EDNS. TYPE1000 has been chosen
for this purpose as IANA is unlikely to allocate this type in the for this purpose as IANA is unlikely to allocate this type in the
near future and it is not in type space reserved for end user near future and it is not in a range reserved for private use
allocation. [RFC6895].
We don't expect any records to be returned in the answer section with We expect no records to be returned in the answer section with the
the rcode set to NOERROR and the AA and QR bits to be set in the rcode set to NOERROR and the AA and QR bits to be set in the
response, RA may also be set [RFC1034]. We do not expect a OPT response. RA may also be set [RFC1034]. We do not expect an OPT
record to be returned [RFC6891]. record to be returned [RFC6891].
Check that queries for an unknown type work: Check that queries for an unknown type work:
dig +noedns +noad +norec type1000 $zone @$server dig +noedns +noad +norec type1000 $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: an empty answer section. expect: an empty answer section.
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
That new types are to be expected is specified in Section 3.6,
[RFC1035]. Servers that don't support a new type are expected to
reject a zone that contains a unsupported type as per Section 5.2,
[RFC1035]. This means that a server that does load a zone can answer
questions for unknown types with NOERROR or NXDOMAIN as per
Section 4.3.2, [RFC1034]. [RFC6895] later reserved distinct ranges
for meta and data types which allows servers to be definitive about
whether a query should be answerable from zone content or not.
8.1.3. Testing Header Bits 8.1.3. Testing Header Bits
8.1.3.1. Testing CD=1 Queries 8.1.3.1. Testing CD=1 Queries
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with only the CD DNS flag bit set and to serve. This query is made with only the CD DNS flag bit set and
all other DNS bits clear and without EDNS. all other DNS bits clear and without EDNS.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response. We do not expect a OPT record to be returned. set in the response. We do not expect an OPT record to be returned.
If the server supports DNSSEC, CD should be set in the response If the server supports DNSSEC, CD should be set in the response
[RFC4035] otherwise CD should be clear [RFC1034]. [RFC4035] otherwise CD should be clear [RFC1034].
Check that queries with CD=1 work: Check that queries with CD=1 work:
dig +noedns +noad +norec +cd soa $zone @$server dig +noedns +noad +norec +cd soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
CD use in queries is defined in [RFC4035].
8.1.3.2. Testing AD=1 Queries 8.1.3.2. Testing AD=1 Queries
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with only the AD DNS flag bit set and to serve. This query is made with only the AD DNS flag bit set and
all other DNS bits clear and without EDNS. all other DNS bits clear and without EDNS.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response. We do not expect a OPT record to be returned. set in the response. We do not expect an OPT record to be returned.
The purpose of this query is to detect blocking of queries with the
If the server supports DNSSEC, AD may be set in the response AD bit present, not the specific value of AD in the response.
[RFC6840] otherwise AD should be clear [RFC1034].
Check that queries with AD=1 work: Check that queries with AD=1 work:
dig +noedns +norec +ad soa $zone @$server dig +noedns +norec +ad soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
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8.1.3.3. Testing Reserved Bit 8.1.3.3. Testing Reserved Bit
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with only the final reserved DNS flag to serve. This query is made with only the final reserved DNS flag
bit set and all other DNS bits clear and without EDNS. bit set and all other DNS bits clear and without EDNS.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may be set. The final reserved bit must not set in the response, RA may be set. The final reserved bit must not
be set [RFC1034]. We do not expect a OPT record to be returned be set [RFC1034]. We do not expect an OPT record to be returned
[RFC6891]. [RFC6891].
Check that queries with the last unassigned DNS header flag work and Check that queries with the last unassigned DNS header flag work and
that the flag bit is not copied to the response: that the flag bit is not copied to the response:
dig +noedns +noad +norec +zflag soa $zone @$server dig +noedns +noad +norec +zflag soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: MBZ to NOT be in the response expect: MBZ to NOT be in the response (see below)
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
MBZ (Must Be Zero) presence indicates the flag bit has been MBZ (Must Be Zero) is a dig-specific indication that the flag bit has
incorrectly copied. See Section 4.1.1, [RFC1035] "Z Reserved for been incorrectly copied. See Section 4.1.1, [RFC1035] "Z Reserved
future use. Must be zero in all queries and responses." for future use. Must be zero in all queries and responses."
8.1.4. Testing Unknown Opcodes 8.1.4. Testing Unknown Opcodes
Construct a DNS message that consists of only a DNS header with Construct a DNS message that consists of only a DNS header with
opcode set to 15 (currently not allocated), no DNS header bits set opcode set to 15 (currently not allocated), no DNS header bits set
and empty question, answer, authority and additional sections. and empty question, answer, authority and additional sections.
Check that new opcodes are handled: Check that new opcodes are handled:
dig +noedns +noad +opcode=15 +norec +header-only @$server dig +noedns +noad +opcode=15 +norec +header-only @$server
expect: status: NOTIMP expect: status: NOTIMP
expect: SOA record to NOT be present expect: opcode: 15
expect: all sections to be empty
expect: flag: aa to NOT be present expect: flag: aa to NOT be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
expect: the OPT record to NOT be present expect: the OPT record to NOT be present
As unknown opcodes have no definition, including packet format other
than there must be a DNS header present (QR, OPCODE and RCODE are the
only header fields that need to be common across all opcodes,
everything else in the header can potentially be redefined), there is
only one possible rcode that make sense to return to a request with a
unknown opcode and that is NOTIMP.
8.1.5. Testing Recursive Queries 8.1.5. Testing Recursive Queries
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with only the RD DNS flag bit set and to serve. This query is made with only the RD DNS flag bit set and
without EDNS. without EDNS.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA, QR and RD bits to section with the rcode set to NOERROR and the AA, QR and RD bits to
be set in the response, RA may also be set [RFC1034]. We do not be set in the response, RA may also be set [RFC1034]. We do not
expect a OPT record to be returned [RFC6891]. expect an OPT record to be returned [RFC6891].
Check that recursive queries work: Check that recursive queries work:
dig +noedns +noad +rec soa $zone @$server dig +noedns +noad +rec soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to be present expect: flag: rd to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
skipping to change at page 15, line 36 skipping to change at page 14, line 48
8.1.6. Testing TCP 8.1.6. Testing TCP
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set and without to serve. This query is made with no DNS flag bits set and without
EDNS. This query is to be sent using TCP. EDNS. This query is to be sent using TCP.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We do not expect set in the response, RA may also be set [RFC1034]. We do not expect
a OPT record to be returned [RFC6891]. an OPT record to be returned [RFC6891].
Check that TCP queries work: Check that TCP queries work:
dig +noedns +noad +norec +tcp soa $zone @$server dig +noedns +noad +norec +tcp soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: rd to NOT be present expect: flag: rd to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
skipping to change at page 16, line 21 skipping to change at page 15, line 34
EDNS support. EDNS support.
8.2.1. Testing Minimal EDNS 8.2.1. Testing Minimal EDNS
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 0 is used without any EDNS options or EDNS flags set. version 0 is used without any EDNS options or EDNS flags set.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We expect a OPT set in the response, RA may also be set [RFC1034]. We expect an OPT
record to be returned. There should be no EDNS flags present in the record to be returned. There should be no EDNS flags present in the
response. The EDNS version field should be zero and there should be response. The EDNS version field should be zero and there should be
no EDNS options present [RFC6891]. no EDNS options present [RFC6891].
Check that plain EDNS queries work: Check that plain EDNS queries work:
dig +nocookie +edns=0 +noad +norec soa $zone @$server dig +nocookie +edns=0 +noad +norec soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
+nocookie disables sending a EDNS COOKIE option in which is on by +nocookie disables sending a EDNS COOKIE option in which is on by
default in BIND 9.11.0. default in BIND 9.11.0.
8.2.2. Testing EDNS Version Negotiation 8.2.2. Testing EDNS Version Negotiation
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 1 is used without any EDNS options or EDNS flags set. version 1 is used without any EDNS options or EDNS flags set.
We expect the SOA record for the zone to NOT be returned in the We expect the SOA record for the zone to NOT be returned in the
answer section with the extended rcode set to BADVERS and the QR bit answer section with the extended rcode set to BADVERS and the QR bit
to be set in the response, RA may also be set [RFC1034]. We expect a to be set in the response, RA may also be set [RFC1034]. We expect
OPT record to be returned. There should be no EDNS flags present in an OPT record to be returned. There should be no EDNS flags present
the response. The EDNS version field should be zero as EDNS versions in the response. The EDNS version field should be zero as EDNS
other than 0 are yet to be specified and there should be no EDNS versions other than 0 are yet to be specified and there should be no
options present [RFC6891]. EDNS options present [RFC6891].
Check that EDNS version 1 queries work (EDNS supported): Check that EDNS version 1 queries work (EDNS supported):
dig +nocookie +edns=1 +noednsneg +noad +norec soa $zone @$server dig +nocookie +edns=1 +noednsneg +noad +norec soa $zone @$server
expect: status: BADVERS expect: status: BADVERS
expect: the SOA record to NOT be present in the answer section expect: the SOA record to NOT be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to NOT be present expect: flag: aa to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
Only EDNS Version 0 is currently defined so the response should Only EDNS Version 0 is currently defined so the response should
always be a 0 version. This will change when EDNS version 1 is always be a 0 version. This will change when EDNS version 1 is
defined. BADVERS is the expected rcode if EDNS is supported as per defined. BADVERS is the expected rcode if EDNS is supported as per
Section 6.1.3, [RFC6891]. Section 6.1.3, [RFC6891].
8.2.3. Testing Unknown EDNS Options 8.2.3. Testing Unknown EDNS Options
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 0 is used without any EDNS flags. A EDNS option is present version 0 is used without any EDNS flags. A EDNS option is present
with a value from the yet to be assigned range. The unassigned value with a value from the yet to be assigned range. The unassigned value
chosen is 100 and will need to be adjusted when IANA assigns this chosen is 100 and will need to be adjusted when IANA assigns this
value formally. value formally.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We expect a OPT set in the response, RA may also be set [RFC1034]. We expect an OPT
record to be returned. There should be no EDNS flags present in the record to be returned. There should be no EDNS flags present in the
response. The EDNS version field should be zero as EDNS versions response. The EDNS version field should be zero as EDNS versions
other than 0 are yet to be specified and there should be no EDNS other than 0 are yet to be specified and there should be no EDNS
options present as unknown EDNS options are supposed to be ignored by options present as unknown EDNS options are supposed to be ignored by
the server [RFC6891]. the server [RFC6891].
Check that EDNS queries with an unknown option work (EDNS supported): Check that EDNS queries with an unknown option work (EDNS supported):
dig +nocookie +edns=0 +noad +norec +ednsopt=100 soa $zone @$server dig +nocookie +edns=0 +noad +norec +ednsopt=100 soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: OPT=100 to NOT be present expect: OPT=100 to NOT be present
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
Unknown EDNS options are supposed to be ignored, Section 6.1.2, Unknown EDNS options are supposed to be ignored, Section 6.1.2,
[RFC6891]. [RFC6891].
8.2.4. Testing Unknown EDNS Flags 8.2.4. Testing Unknown EDNS Flags
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 0 is used without any EDNS options. A unassigned EDNS flag version 0 is used without any EDNS options. A unassigned EDNS flag
bit is set (0x40 in this case). bit is set (0x40 in this case).
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We expect a OPT set in the response, RA may also be set [RFC1034]. We expect an OPT
record to be returned. There should be no EDNS flags present in the record to be returned. There should be no EDNS flags present in the
response as unknown EDNS flags are supposed to be ignored. The EDNS response as unknown EDNS flags are supposed to be ignored. The EDNS
version field should be zero and there should be no EDNS options version field should be zero and there should be no EDNS options
present [RFC6891]. present [RFC6891].
Check that EDNS queries with unknown flags work (EDNS supported): Check that EDNS queries with unknown flags work (EDNS supported):
dig +nocookie +edns=0 +noad +norec +ednsflags=0x40 soa $zone @$server dig +nocookie +edns=0 +noad +norec +ednsflags=0x40 soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: MBZ not to be present expect: MBZ not to be present
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
MBZ (Must Be Zero) presence indicates the flag bit has been MBZ (Must Be Zero) presence indicates the flag bit has been
incorrectly copied as per Section 6.1.4, [RFC6891]. incorrectly copied as per Section 6.1.4, [RFC6891].
8.2.5. Testing EDNS Version Negotiation With Unknown EDNS Flags 8.2.5. Testing EDNS Version Negotiation With Unknown EDNS Flags
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 1 is used without any EDNS options. A unassigned EDNS flag version 1 is used without any EDNS options. A unassigned EDNS flag
bit is set (0x40 in this case). bit is set (0x40 in this case).
We expect the SOA record for the zone to NOT be returned in the We expect the SOA record for the zone to NOT be returned in the
answer section with the extended rcode set to BADVERS and the QR bit answer section with the extended rcode set to BADVERS and the QR bit
to be set in the response, RA may also be set [RFC1034]. We expect a to be set in the response, RA may also be set [RFC1034]. We expect
OPT record to be returned. There should be no EDNS flags present in an OPT record to be returned. There should be no EDNS flags present
the response as unknown EDNS flags are supposed to be ignored. The in the response as unknown EDNS flags are supposed to be ignored.
EDNS version field should be zero as EDNS versions other than 0 are The EDNS version field should be zero as EDNS versions other than 0
yet to be specified and there should be no EDNS options present are yet to be specified and there should be no EDNS options present
[RFC6891]. [RFC6891].
Check that EDNS version 1 queries with unknown flags work (EDNS Check that EDNS version 1 queries with unknown flags work (EDNS
supported): supported):
dig +nocookie +edns=1 +noednsneg +noad +norec +ednsflags=0x40 soa \ dig +nocookie +edns=1 +noednsneg +noad +norec +ednsflags=0x40 soa \
$zone @$server $zone @$server
expect: status: BADVERS expect: status: BADVERS
expect: SOA record to NOT be present expect: SOA record to NOT be present
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: MBZ not to be present expect: MBZ not to be present
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to NOT be present expect: flag: aa to NOT be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
+noednsneg disables EDNS version negotiation in DiG; MBZ (Must Be +noednsneg disables EDNS version negotiation in DiG; MBZ (Must Be
Zero) presence indicates the flag bit has been incorrectly copied. Zero) presence indicates the flag bit has been incorrectly copied.
8.2.6. Testing EDNS Version Negotiation With Unknown EDNS Options 8.2.6. Testing EDNS Version Negotiation With Unknown EDNS Options
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 1 is used. A unknown EDNS option is present (option code 100 version 1 is used. A unknown EDNS option is present (option code 100
has been chosen). has been chosen).
We expect the SOA record for the zone to NOT be returned in the We expect the SOA record for the zone to NOT be returned in the
answer section with the extended rcode set to BADVERS and the QR bit answer section with the extended rcode set to BADVERS and the QR bit
to be set in the response, RA may also be set [RFC1034]. We expect a to be set in the response, RA may also be set [RFC1034]. We expect
OPT record to be returned. There should be no EDNS flags present in an OPT record to be returned. There should be no EDNS flags present
the response. The EDNS version field should be zero as EDNS versions in the response. The EDNS version field should be zero as EDNS
other than 0 are yet to be specified and there should be no EDNS versions other than 0 are yet to be specified and there should be no
options present [RFC6891]. EDNS options present [RFC6891].
Check that EDNS version 1 queries with unknown options work (EDNS Check that EDNS version 1 queries with unknown options work (EDNS
supported): supported):
dig +nocookie +edns=1 +noednsneg +noad +norec +ednsopt=100 soa \ dig +nocookie +edns=1 +noednsneg +noad +norec +ednsopt=100 soa \
$zone @$server $zone @$server
expect: status: BADVERS expect: status: BADVERS
expect: SOA record to NOT be present expect: SOA record to NOT be present
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: OPT=100 to NOT be present expect: OPT=100 to NOT be present
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
+noednsneg disables EDNS version negotiation in DiG. +noednsneg disables EDNS version negotiation in DiG.
8.2.7. Testing Truncated Responses 8.2.7. Testing Truncated Responses
Ask for the DNSKEY records of the zone the server is nominally Ask for the DNSKEY records of the zone the server is nominally
configured to serve. This query is made with no DNS flag bits set. configured to serve. This query is made with no DNS flag bits set.
EDNS version 0 is used without any EDNS options. The only EDNS flag EDNS version 0 is used without any EDNS options. The only EDNS flag
set is DO. The EDNS UDP buffer size is set to 512. The intention of set is DO. The EDNS UDP buffer size is set to 512. The intention of
this query is elicit a truncated response from the server. Most this query is elicit a truncated response from the server. Most
signed DNSKEY responses are bigger than 512 bytes. signed DNSKEY responses are bigger than 512 bytes.
We expect a response with the rcode set to NOERROR and the AA and QR We expect a response with the rcode set to NOERROR and the AA and QR
bits to be set, AD may be set in the response if the server supports bits to be set, AD may be set in the response if the server supports
DNSSEC otherwise it should be clear. TC and RA may also be set DNSSEC otherwise it should be clear. TC and RA may also be set
[RFC1034]. We expect a OPT record to be present in the response. [RFC1034]. We expect an OPT record to be present in the response.
There should be no EDNS flags other than DO present in the response. There should be no EDNS flags other than DO present in the response.
The EDNS version field should be zero and there should be no EDNS The EDNS version field should be zero and there should be no EDNS
options present [RFC6891]. options present [RFC6891].
If TC is not set it is not possible to confirm that the server If TC is not set it is not possible to confirm that the server
correctly adds the OPT record to the truncated responses or not. correctly adds the OPT record to the truncated responses or not.
dig +norec +dnssec +bufsize=512 +ignore dnskey $zone @$server dig +norec +dnssec +bufsize=512 +ignore dnskey $zone @$server
expect: NOERROR expect: NOERROR
expect: OPT record with version set to 0 expect: OPT record with version set to 0
skipping to change at page 20, line 40 skipping to change at page 20, line 9
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 0 is used without any EDNS options. The only EDNS flag set version 0 is used without any EDNS options. The only EDNS flag set
is DO. is DO.
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, AD may be set in the response if the server set in the response, AD may be set in the response if the server
supports DNSSEC otherwise it should be clear. RA may also be set supports DNSSEC otherwise it should be clear. RA may also be set
[RFC1034]. We expect a OPT record to be returned. There should be [RFC1034]. We expect an OPT record to be returned. There should be
no EDNS flags other than DO present in the response which should be no EDNS flags other than DO present in the response which should be
present if the server supports DNSSEC. The EDNS version field should present if the server supports DNSSEC. The EDNS version field should
be zero and there should be no EDNS options present [RFC6891]. be zero and there should be no EDNS options present [RFC6891].
Check that a DNSSEC queries work (EDNS supported): Check that a DNSSEC queries work (EDNS supported):
dig +nocookie +edns=0 +noad +norec +dnssec soa $zone @$server dig +nocookie +edns=0 +noad +norec +dnssec soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: DO=1 to be present if a RRSIG is in the response expect: DO=1 to be present if a RRSIG is in the response
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
DO=1 should be present if RRSIGs are returned as they indicate that DO=1 should be present if RRSIGs are returned as they indicate that
the server supports DNSSEC. Servers that support DNSSEC are supposed the server supports DNSSEC. Servers that support DNSSEC are supposed
to copy the DO bit from the request to the response as per [RFC3225]. to copy the DO bit from the request to the response as per [RFC3225].
8.2.9. Testing EDNS Version Negotiation With DNSSEC 8.2.9. Testing EDNS Version Negotiation With DNSSEC
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 1 is used without any EDNS options. The only EDNS flag set version 1 is used without any EDNS options. The only EDNS flag set
is DO. is DO.
We expect the SOA record for the zone to NOT be returned in the We expect the SOA record for the zone to NOT be returned in the
answer section with the rcode set to BADVERS and the only the QR bit answer section with the rcode set to BADVERS and the only the QR bit
and possibly the RA bit to be set [RFC1034]. We expect a OPT record and possibly the RA bit to be set [RFC1034]. We expect an OPT record
to be returned. There should be no EDNS flags other than DO present to be returned. There should be no EDNS flags other than DO present
in the response which should be present if the server supports in the response which should be present if the server supports
DNSSEC. The EDNS version field should be zero and there should be no DNSSEC. The EDNS version field should be zero and there should be no
EDNS options present [RFC6891]. EDNS options present [RFC6891].
Check that EDNS version 1 DNSSEC queries work (EDNS supported): Check that EDNS version 1 DNSSEC queries work (EDNS supported):
dig +nocookie +edns=1 +noednsneg +noad +norec +dnssec soa \ dig +nocookie +edns=1 +noednsneg +noad +norec +dnssec soa \
$zone @$server $zone @$server
expect: status: BADVERS expect: status: BADVERS
expect: SOA record to NOT be present expect: SOA record to NOT be present
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: DO=1 to be present if the EDNS version 0 DNSSEC query test expect: DO=1 to be present if the EDNS version 0 DNSSEC query test
returned DO=1 returned DO=1
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to NOT be present expect: flag: aa to NOT be present
+noednsneg disables EDNS version negotiation in DiG. +noednsneg disables EDNS version negotiation in DiG.
8.2.10. Testing With Multiple Defined EDNS Options 8.2.10. Testing With Multiple Defined EDNS Options
Ask for the SOA record of the zone the server is nominally configured Ask for the SOA record of the zone the server is nominally configured
to serve. This query is made with no DNS flag bits set. EDNS to serve. This query is made with no DNS flag bits set. EDNS
version 0 is used. A number of defined EDNS options are present version 0 is used. A number of defined EDNS options are present
(NSID [RFC5001], DNS COOKIE [RFC7873], EDNS Client Subnet [RFC7871] (NSID [RFC5001], DNS COOKIE [RFC7873], EDNS Client Subnet [RFC7871]
and EDNS Expire [RFC7314]). and EDNS Expire [RFC7314]).
We expect the SOA record for the zone to be returned in the answer We expect the SOA record for the zone to be returned in the answer
section with the rcode set to NOERROR and the AA and QR bits to be section with the rcode set to NOERROR and the AA and QR bits to be
set in the response, RA may also be set [RFC1034]. We expect a OPT set in the response, RA may also be set [RFC1034]. We expect an OPT
record to be returned. There should be no EDNS flags present in the record to be returned. There should be no EDNS flags present in the
response. The EDNS version field should be zero. Any of the response. The EDNS version field should be zero. Any of the
requested EDNS options supported by the server and permitted server requested EDNS options supported by the server and permitted server
configuration may be returned [RFC6891]. configuration may be returned [RFC6891].
Check that EDNS queries with multiple defined EDNS options work: Check that EDNS queries with multiple defined EDNS options work:
dig +edns=0 +noad +norec +cookie +nsid +expire +subnet=0.0.0.0/0 \ dig +edns=0 +noad +norec +cookie +nsid +expire +subnet=0.0.0.0/0 \
soa $zone @$server soa $zone @$server
expect: status: NOERROR expect: status: NOERROR
expect: the SOA record to be present in the answer section expect: the SOA record to be present in the answer section
expect: a OPT record to be present in the additional section expect: an OPT record to be present in the additional section
expect: EDNS Version 0 in response expect: EDNS Version 0 in response
expect: flag: aa to be present expect: flag: aa to be present
expect: flag: ad to NOT be present expect: flag: ad to NOT be present
8.3. When EDNS Is Not Supported 8.3. When EDNS Is Not Supported
If EDNS is not supported by the nameserver, we expect a response to If EDNS is not supported by the nameserver, we expect a response to
all the above queries. That response may be a FORMERR or NOTIMP all the above queries. That response may be a FORMERR or NOTIMP
error response or the OPT record may just be ignored. error response or the OPT record may just be ignored.
skipping to change at page 25, line 25 skipping to change at page 24, line 39
D. Wessels, "DNS Transport over TCP - Implementation D. Wessels, "DNS Transport over TCP - Implementation
Requirements", RFC 7766, DOI 10.17487/RFC7766, March 2016, Requirements", RFC 7766, DOI 10.17487/RFC7766, March 2016,
<https://www.rfc-editor.org/info/rfc7766>. <https://www.rfc-editor.org/info/rfc7766>.
12.2. Informative References 12.2. Informative References
[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>.
[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, DOI 10.17487/RFC3597, September
2003, <https://www.rfc-editor.org/info/rfc3597>.
[RFC5001] Austein, R., "DNS Name Server Identifier (NSID) Option", [RFC5001] Austein, R., "DNS Name Server Identifier (NSID) Option",
RFC 5001, DOI 10.17487/RFC5001, August 2007, RFC 5001, DOI 10.17487/RFC5001, August 2007,
<https://www.rfc-editor.org/info/rfc5001>. <https://www.rfc-editor.org/info/rfc5001>.
[RFC7314] Andrews, M., "Extension Mechanisms for DNS (EDNS) EXPIRE [RFC7314] Andrews, M., "Extension Mechanisms for DNS (EDNS) EXPIRE
Option", RFC 7314, DOI 10.17487/RFC7314, July 2014, Option", RFC 7314, DOI 10.17487/RFC7314, July 2014,
<https://www.rfc-editor.org/info/rfc7314>. <https://www.rfc-editor.org/info/rfc7314>.
[RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W. [RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W.
Kumari, "Client Subnet in DNS Queries", RFC 7871, Kumari, "Client Subnet in DNS Queries", RFC 7871,
DOI 10.17487/RFC7871, May 2016, DOI 10.17487/RFC7871, May 2016,
<https://www.rfc-editor.org/info/rfc7871>. <https://www.rfc-editor.org/info/rfc7871>.
[RFC7873] Eastlake 3rd, D. and M. Andrews, "Domain Name System (DNS) [RFC7873] Eastlake 3rd, D. and M. Andrews, "Domain Name System (DNS)
Cookies", RFC 7873, DOI 10.17487/RFC7873, May 2016, Cookies", RFC 7873, DOI 10.17487/RFC7873, May 2016,
<https://www.rfc-editor.org/info/rfc7873>. <https://www.rfc-editor.org/info/rfc7873>.
Author's Address Authors' Addresses
M. Andrews M. Andrews
Internet Systems Consortium Internet Systems Consortium
950 Charter Street 950 Charter Street
Redwood City, CA 94063 Redwood City, CA 94063
US US
Email: marka@isc.org Email: marka@isc.org
Ray Bellis
Internet Systems Consortium
950 Charter Street
Redwood City, CA 94063
US
Email: ray@isc.org
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