draft-ietf-dprive-unauth-to-authoritative-03.txt   draft-ietf-dprive-unauth-to-authoritative-04.txt 
Network Working Group P. Hoffman Network Working Group P. Hoffman
Internet-Draft ICANN Internet-Draft ICANN
Intended status: Experimental P. van Dijk Intended status: Experimental P. van Dijk
Expires: January 13, 2022 PowerDNS Expires: 1 April 2022 PowerDNS
July 12, 2021 28 September 2021
Recursive to Authoritative DNS with Unauthenticated Encryption Recursive to Authoritative DNS with Unauthenticated Encryption
draft-ietf-dprive-unauth-to-authoritative-03 draft-ietf-dprive-unauth-to-authoritative-04
Abstract Abstract
This document describes a use case and a method for a DNS recursive This document describes a use case and a method for a DNS recursive
resolver to use unauthenticated encryption when communicating with resolver to use unauthenticated encryption when communicating with
authoritative servers. The motivating use case for this method is authoritative servers. The motivating use case for this method is
that more encryption on the Internet is better, and some resolver that more encryption on the Internet is better, and some resolver
operators believe that unauthenticated encryption is better than no operators believe that unauthenticated encryption is better than no
encryption at all. The method described here is optional for both encryption at all. The method described here is optional for both
the recursive resolver and the authoritative server. This method the recursive resolver and the authoritative server.
supports unauthenticated encryption using the same mechanism for
discovery of encryption support for the server as [FULL-AUTH].
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 13, 2022. This Internet-Draft will expire on 1 April 2022.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Use Case for Unauthenticated Encryption . . . . . . . . . 3 1.1. Use Case for Unauthenticated Encryption . . . . . . . . . 3
1.2. Summary of Protocol . . . . . . . . . . . . . . . . . . . 3 1.2. Summary of Protocol . . . . . . . . . . . . . . . . . . . 3
1.3. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4 1.3. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4
2. Discovery of Authoritative Server Encryption . . . . . . . . 4 2. Discovery of Authoritative Server Encryption . . . . . . . . 4
3. Processing Discovery Responses . . . . . . . . . . . . . . . 5 3. Processing Discovery Responses . . . . . . . . . . . . . . . 5
3.1. Resolver Process as Pseudocode . . . . . . . . . . . . . 6 3.1. Resolver Process as Pseudocode . . . . . . . . . . . . . 6
3.2. Resolver Session Failures . . . . . . . . . . . . . . . . 7 3.2. Resolver Session Failures . . . . . . . . . . . . . . . . 7
4. Serving with Encryption . . . . . . . . . . . . . . . . . . . 7 4. Serving with Encryption . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 8 8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
A recursive resolver using traditional DNS over port 53 may wish A recursive resolver using traditional DNS over port 53 may wish
instead to use encrypted communication with authoritative servers in instead to use encrypted communication with authoritative servers in
order to limit snooping of its DNS traffic by passive or on-path order to limit snooping of its DNS traffic by passive or on-path
attackers. The recursive resolver can use unauthenticated encryption attackers. The recursive resolver can use unauthenticated encryption
(defined in [OPPORTUN]) to achieve this goal. (defined in [OPPORTUN]) to achieve this goal.
This document describes the use case for unauthenticated encryption This document describes the use case for unauthenticated encryption
in recursive resolvers in Section 1.1. The encryption method with in recursive resolvers in Section 1.1. The encryption method with
authoritative servers can be DNS-over-TLS [DNSOTLS] (DoT), DNS-over- authoritative servers can be DNS-over-TLS [DNS-OVER-TLS] (DoT), DNS-
HTTPS [DNSOHTTPS] (DoH), and/or DNS-over-QUIC [DNSOQUIC] (DoQ). over-HTTPS [DNS-OVER-HTTPS] (DoH), and/or DNS-over-QUIC
[DNS-OVER-QUIC] (DoQ).
The document also describes a discovery method that shows if an The document also describes a discovery method that shows if an
authoritative server supports encryption in Section 2. authoritative server supports encryption in Section 2.
See [FULL-AUTH] for a description of the use case and a proposed See [FULL-AUTH] for a description of the use case and a proposed
mechanism for fully-authenticated encryption. mechanism for fully-authenticated encryption.
NOTE: The draft uses the SVCB record as a discovery mechanism for NOTE: The draft uses the SVCB record as a discovery mechanism for
encryption by a particular authoritative server. Any record type encryption by a particular authoritative server. Any record type
that can show multiple types of encryption (currently DoT, DoH, and that can show multiple types of encryption (currently DoT, DoH, and
skipping to change at page 3, line 16 skipping to change at page 3, line 20
1.1. Use Case for Unauthenticated Encryption 1.1. Use Case for Unauthenticated Encryption
The use case in this document for unauthenticated encryption is The use case in this document for unauthenticated encryption is
recursive resolver operators who are happy to use encryption with recursive resolver operators who are happy to use encryption with
authoritative servers if doing so doesn't significantly slow down authoritative servers if doing so doesn't significantly slow down
getting answers, and authoritative server operators that are happy to getting answers, and authoritative server operators that are happy to
use encryption with recursive resolvers if it doesn't cost much. In use encryption with recursive resolvers if it doesn't cost much. In
this use case, resolvers do not want to return an error for requests this use case, resolvers do not want to return an error for requests
that were sent over an encrypted channel if they would have been able that were sent over an encrypted channel if they would have been able
to give a correct answer using unencrypted transport. to give a correct answer using unencrypted transport. Ultimately,
this effort has two two goals: to protect queries from failing in
case authenticated encryption is not available, and to enable
recursive resolver operators to encrypt without server
authentication.
Resolvers and authoritative servers understand that using encryption Resolvers and authoritative servers understand that using encryption
costs something, but are willing to absorb the costs for the benefit costs something, but are willing to absorb the costs for the benefit
of more Internet traffic being encrypted. The extra costs (compared of more Internet traffic being encrypted. The extra costs (compared
to using traditional DNS on port 53) include: to using traditional DNS on port 53) include:
o Extra round trips to establish TCP for every session (but not * Extra round trips to establish TCP for every session (but not
necessarily for every query) necessarily for every query)
o Extra round trips for TLS establishment * Extra round trips for TLS establishment
o Greater CPU use for TLS establishment * Greater CPU use for TLS establishment
o Greater CPU use for encryption after TLS establishment * Greater CPU use for encryption after TLS establishment
o Greater memory use for holding TLS state * Greater memory use for holding TLS state
This use case is not expected to apply to all resolvers or This use case is not expected to apply to all resolvers or
authoritative servers. For example, according to [RSO_STATEMENT], authoritative servers. For example, according to [RSO_STATEMENT],
some root server operators do not want to be the early adopters for some root server operators do not want to be the early adopters for
DNS with encryption. The protocol in this document explicitly allows DNS with encryption. The protocol in this document explicitly allows
authoritative servers to signal when they are ready to begin offering authoritative servers to signal when they are ready to begin offering
DNS with encryption. DNS with encryption.
1.2. Summary of Protocol 1.2. Summary of Protocol
This summary gives an overview of how the parts of the protocol work This summary gives an overview of how the parts of the protocol work
together. together.
o The resolver discovers whether any authoritative server of * The resolver discovers whether any authoritative server of
interest supports DNS with encryption by querying for the SVCB interest supports DNS with encryption by querying for the SVCB
records [SVCB]. As described in [DNS-SVCB], SVCB records can records [SVCB]. As described in [DNS-SVCB], SVCB records can
indicate that a server supports encrypted transport of DNS indicate that a server supports encrypted transport of DNS
queries. queries.
NOTE: In this document, the term "SVCB record" is used _only_ for NOTE: In this document, the term "SVCB record" is used _only_ for
SVCB records that indicate encryption as described in [DNS-SVCB]. SVCB records that indicate encryption as described in [DNS-SVCB].
SVCB records that do not have these indicators in the RDATA are SVCB records that do not have these indicators in the RDATA are
not included in the term "SVCB record" in this document. not included in the term "SVCB record" in this document.
o The resolver uses any authoritative server with a SVCB record that * The resolver uses any authoritative server with a SVCB record that
indicates encryption to perform unauthenticated encryption. indicates encryption to perform unauthenticated encryption.
o The resolver does not fail to set up encryption if the * The resolver does not fail to set up encryption if server
authentication in the TLS session fails. authentication in the TLS session fails.
1.3. Definitions 1.3. Definitions
The terms "recursive resolver", "authoritative server", and "classic The terms "recursive resolver", "authoritative server", and "classic
DNS" are defined in [DNS-TERM]. DNS" are defined in [DNS-TERM].
"DNS with encryption" means transport of DNS over any of DoT, DoH, or "DNS with encryption" means transport of DNS over any of DoT, DoH, or
DoQ. A server that supports DNS with encryption supports transport DoQ. A server that supports DNS with encryption supports transport
over one or more of DoT, DoH, or DoQ. over one or more of DoT, DoH, or DoQ.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [MUSTSHOULD1] [MUSTSHOULD2] when, and only when, they appear in 14 [MUST-SHOULD-1] [MUST-SHOULD-2] when, and only when, they appear
all capitals, as shown here. in all capitals, as shown here.
2. Discovery of Authoritative Server Encryption 2. Discovery of Authoritative Server Encryption
An authoritative server that supports DNS with encryption makes An authoritative server that supports DNS with encryption makes
itself discoverable by publishing one or more DNS SVCB records that itself discoverable by publishing one or more DNS SVCB records that
contain "alpn" parameter keys. SVCB records are defined in [SVCB], contain "alpn" parameter keys. SVCB records are defined in [SVCB],
and the DNS extension to those records is defined in [DNS-SVCB]. and the DNS extension to those records is defined in [DNS-SVCB].
A recursive resolver discovers whether an authoritative server A recursive resolver discovers whether an authoritative server
supports DNS with encryption by looking for cached SVCB records for supports DNS with encryption by looking for cached SVCB records for
skipping to change at page 5, line 35 skipping to change at page 5, line 42
those authoritative servers in the cache are negative responses, the those authoritative servers in the cache are negative responses, the
resolver MUST use classic (unencrypted) DNS instead of encryption. resolver MUST use classic (unencrypted) DNS instead of encryption.
Similarly, if none of the DNS SVCB records for the authoritative Similarly, if none of the DNS SVCB records for the authoritative
servers in the cache have supported "alpn" parameters, the resolver servers in the cache have supported "alpn" parameters, the resolver
MUST use classic (unencrypted) DNS instead of encryption. MUST use classic (unencrypted) DNS instead of encryption.
If there are any DNS SVCB records in the cache for the authoritative If there are any DNS SVCB records in the cache for the authoritative
servers for a zone with supported "alpn" parameters, the resolver servers for a zone with supported "alpn" parameters, the resolver
MUST try each indicated authoritative server using DNS with MUST try each indicated authoritative server using DNS with
encryption until it successfully sets up a connection. The resolver encryption until it successfully sets up a connection. The resolver
only attempts to use the encrypted transports that are in the attempts to use the encrypted transports that are in the associated
associated SVCB record for the authoritative server. (( Note that SVCB record for the authoritative server.
this completely prohibits "simple port 853 probing" even though that
is what some operators are currently doing. Does the WG want to be
this strict? ))
A resolver SHOULD keep a DNS with encryption session to a particular A resolver SHOULD keep a DNS with encryption session to a particular
server open if it expects to send additional queries to that server server open if it expects to send additional queries to that server
in a short period of time. [DNS-OVER-TCP] says "both clients and in a short period of time. [DNS-OVER-TCP] says "both clients and
servers SHOULD support connection reuse" for TCP connections, and servers SHOULD support connection reuse" for TCP connections, and
that advice could apply as well for DNS with encryption, especially that advice could apply as well for DNS with encryption, especially
as DNS with encryption has far greater overhead for re-establishing a as DNS with encryption has far greater overhead for re-establishing a
connection. If the server closes the DNS with encryption session, connection. If the server closes the DNS with encryption session,
the resolver can possibly re-establish a DNS with encryption session the resolver can possibly re-establish a DNS with encryption session
using encrypted session resumption. using encrypted session resumption. Configuration for the maximum
timeout, minimum timeout, and duration of encrypted sessions should
take into consideration the recommendations given in [TCP-TIMEOUT],
[EDNS-TCP], and (for DoH) [HTTP-1.1].
For any DNS with encryption protocols, TLS version 1.3 [TLS-13] or For any DNS with encryption protocols, TLS version 1.3 [TLS-13] or
later MUST be used. later MUST be used.
A resolver following this protocol does not need to authenticate TLS A resolver following this protocol does not need to authenticate TLS
servers. Thus, when setting up a TLS connection, if the server's servers. Thus, when setting up a TLS connection, if the server's
authentication credentials do not match those expected by the authentication credentials do not match those expected by the
resolver, the resolver continues with the TLS connection. Privacy- resolver, the resolver continues with the TLS connection. Privacy-
oriented resolvers (defined in [PRIVACY-REC]) following this protocol oriented resolvers (defined in [PRIVACY-REC]) following this protocol
MUST NOT indicate that they are using encryption because this MUST NOT indicate that they are using encryption because this
protocol is susceptible to on-path attacks. protocol is susceptible to on-path attacks.
If the resolver gets a TLS failure (such as those listed in
Section 3.2, the resolver instead uses classic DNS on any of the
authoritative servers.
3.1. Resolver Process as Pseudocode 3.1. Resolver Process as Pseudocode
This section is meant as an informal clarification of the protocol, This section is meant as an informal clarification of the protocol,
and is not normative. The pseudocode here is designed to show the and is not normative. The pseudocode here is designed to show the
intent of the protocol, so it is not optimized for things like intent of the protocol, so it is not optimized for things like
intersection of sets and other shortcuts. intersection of sets and other shortcuts.
In this code, "signal_rrset(this_name)" means an "SVCB" query for the In this code, signal_rrset(this_name) means an SVCB query for the
"'_dns'" prefix of "this_name". The "Query over secure transport '_dns' prefix of this_name. The Query over secure transport until
until successful" section ignores differences in name server successful section ignores differences in name server selection and
selection and retry behaviour in different resolvers. retry behaviour in different resolvers.
# Inputs # Inputs
ns_names = List of NS Rdatas from the NS RRset for the queried name ns_names = List of NS Rdatas from the NS RRset for the queried name
can_do_secure = List of secure transports supported by resolver can_do_secure = List of secure transports supported by resolver
secure_names_and_transports = Empty list, filled in below secure_names_and_transports = Empty list, filled in below
# Fill secure_names_and_transports with (name, transport) tuples # Fill secure_names_and_transports with (name, transport) tuples
for this_name in ns_names: for this_name in ns_names:
if signal_rrset(this_name) is in the resolver cache: if signal_rrset(this_name) is in the resolver cache:
if signal_rrset(this_name) positively does not exist: if signal_rrset(this_name) positively does not exist:
skipping to change at page 6, line 52 skipping to change at page 7, line 29
queue a query for signal_rrset(this_name) for later caching queue a query for signal_rrset(this_name) for later caching
# Query over secure transport until successful # Query over secure transport until successful
for (this_name, this_transport) tuple in secure_names_and_transports: for (this_name, this_transport) tuple in secure_names_and_transports:
query using this_transport on this_name query using this_transport on this_name
if successful: if successful:
finished finished
# Got here if no this_name/this_transport query was successful # Got here if no this_name/this_transport query was successful
# or if secure_names_and_transports was empty # or if secure_names_and_transports was empty
query using classic DNS on any/all ns_names; finished query using classic DNS; finished
3.2. Resolver Session Failures 3.2. Resolver Session Failures
The following are some of the reasons that a DNS with encryption The following are some of the reasons that a DNS with encryption
session might fail to be set up: session might fail to be set up:
o The resolver receives a TCP RST response * The resolver receives a TCP RST response
o The resolver does not receive replies to TCP or TLS setup (such as * The resolver does not receive replies to TCP or TLS setup (such as
getting the TCP SYN message, the first TLS message, or completing getting the TCP SYN message, the first TLS message, or completing
TLS handshakes) TLS handshakes)
o The TLS handshake gets a definitive failure * The TLS handshake gets a definitive failure
o The encrypted session fails for reasons other than for * The encrypted session fails for reasons other than for
authentication, such as incorrect algorithm choices or TLS record authentication, such as incorrect algorithm choices or TLS record
failures failures
4. Serving with Encryption 4. Serving with Encryption
An operator of an authoritative server following this protocol SHOULD An operator of an authoritative server following this protocol SHOULD
publish SVCB records as described in Section 2. If they cannot publish SVCB records as described in Section 2. If they cannot
publish such records, the security properties of their authoritative publish such records, the security properties of their authoritative
servers will not be found. If an operator wants to test serving servers will not be found. If an operator wants to test serving
using encryption, they can publish SVCB records with short TTLs and using encryption, they can publish SVCB records with short TTLs and
skipping to change at page 8, line 23 skipping to change at page 9, line 5
The method described in this document explicitly allows a resolver to The method described in this document explicitly allows a resolver to
perform DNS communications over traditional unencrypted, perform DNS communications over traditional unencrypted,
unauthenticated DNS on port 53, if it cannot find an authoritative unauthenticated DNS on port 53, if it cannot find an authoritative
server that advertises that it supports encryption. The method server that advertises that it supports encryption. The method
described in this document explicitly allows a resolver using described in this document explicitly allows a resolver using
encryption to choose to allow unauthenticated encryption. In either encryption to choose to allow unauthenticated encryption. In either
of these cases, the resulting communication will be susceptible to of these cases, the resulting communication will be susceptible to
obvious and well-understood attacks from an attacker in the path of obvious and well-understood attacks from an attacker in the path of
the communications. the communications.
[TLS-1.3] specifically warns against anonymous connections because
such connections only provide protection against passive
eavesdropping while failing to protect against active on-path
attacks. Section C.5 of [TLS-1.3] explicitly states applications
MUST NOT use TLS with unverifiable server authentication unless there
is explicit configuration or a specific application profile to do so.
This document is such an application profile.
Encrypting the traffic between resolvers and authoritative servers
does not solve all the privacy issues for resolution. See
[PRIVACY-REC] and [PRIVACY-CONS] for in-depth discussion of the
associated privacy issues.
7. Acknowledgements 7. Acknowledgements
Puneet Sood contributed many ideas to early drafts of this document. Puneet Sood contributed many ideas to early drafts of this document.
The DPRIVE Working Group has contributed many ideas that keep The DPRIVE Working Group has contributed many ideas that keep
shifting the focus and content of this document. shifting the focus and content of this document.
8. References 8. References
8.1. Normative References 8.1. Normative References
[DNS-SVCB] [DNS-SVCB] Schwartz, B., "Service Binding Mapping for DNS Servers",
Schwartz, B., "Service Binding Mapping for DNS Servers", Work in Progress, Internet-Draft, draft-schwartz-svcb-dns-
draft-schwartz-svcb-dns-03 (work in progress), April 2021. 04, 26 July 2021, <https://www.ietf.org/archive/id/draft-
schwartz-svcb-dns-04.txt>.
[DNS-TERM] [DNS-TERM] Hoffman, P. and K. Fujiwara, "DNS Terminology", Work in
Hoffman, P. and K. Fujiwara, "DNS Terminology", draft- Progress, Internet-Draft, draft-ietf-dnsop-rfc8499bis-03,
ietf-dnsop-rfc8499bis-02 (work in progress), June 2021. 28 September 2021, <https://www.ietf.org/archive/id/draft-
ietf-dnsop-rfc8499bis-03.txt>.
[FULL-AUTH] [FULL-AUTH]
Pauly, T., Rescorla, E., Schinazi, D., and C. A. Wood, Pauly, T., Rescorla, E., Schinazi, D., and C. A. Wood,
"Signaling Authoritative DNS Encryption", draft-rescorla- "Signaling Authoritative DNS Encryption", Work in
dprive-adox-latest-00 (work in progress), February 2021. Progress, Internet-Draft, draft-rescorla-dprive-adox-
latest-00, 26 February 2021,
<https://www.ietf.org/archive/id/draft-rescorla-dprive-
adox-latest-00.txt>.
[MUSTSHOULD1] [MUST-SHOULD-1]
Bradner, S., "Key words for use in RFCs to Indicate 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, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[MUSTSHOULD2] [MUST-SHOULD-2]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[OPPORTUN] [OPPORTUN] Dukhovni, V., "Opportunistic Security: Some Protection
Dukhovni, V., "Opportunistic Security: Some Protection
Most of the Time", RFC 7435, DOI 10.17487/RFC7435, Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
December 2014, <https://www.rfc-editor.org/info/rfc7435>. December 2014, <https://www.rfc-editor.org/info/rfc7435>.
[SVCB] Schwartz, B., Bishop, M., and E. Nygren, "Service binding [SVCB] Schwartz, B., Bishop, M., and E. Nygren, "Service binding
and parameter specification via the DNS (DNS SVCB and and parameter specification via the DNS (DNS SVCB and
HTTPS RRs)", draft-ietf-dnsop-svcb-https-06 (work in HTTPS RRs)", Work in Progress, Internet-Draft, draft-ietf-
progress), June 2021. dnsop-svcb-https-07, 5 August 2021,
<https://www.ietf.org/archive/id/draft-ietf-dnsop-svcb-
https-07.txt>.
[TLS-13] Rescorla, E., "The Transport Layer Security (TLS) Protocol [TLS-13] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
8.2. Informative References 8.2. Informative References
[DNS-OVER-HTTPS]
Hoffman, P. and P. McManus, "DNS Queries over HTTPS
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/info/rfc8484>.
[DNS-OVER-QUIC]
Huitema, C., Dickinson, S., and A. Mankin, "Specification
of DNS over Dedicated QUIC Connections", Work in Progress,
Internet-Draft, draft-ietf-dprive-dnsoquic-04, 3 September
2021, <https://www.ietf.org/archive/id/draft-ietf-dprive-
dnsoquic-04.txt>.
[DNS-OVER-TCP] [DNS-OVER-TCP]
Dickinson, J., Dickinson, S., Bellis, R., Mankin, A., and Dickinson, J., Dickinson, S., Bellis, R., Mankin, A., and
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>.
[DNSOHTTPS] [DNS-OVER-TLS]
Hoffman, P. and P. McManus, "DNS Queries over HTTPS Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/info/rfc8484>.
[DNSOQUIC]
Huitema, C., Mankin, A., and S. Dickinson, "Specification
of DNS over Dedicated QUIC Connections", draft-ietf-
dprive-dnsoquic-02 (work in progress), February 2021.
[DNSOTLS] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "Specification for DNS over Transport and P. Hoffman, "Specification for DNS over Transport
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
2016, <https://www.rfc-editor.org/info/rfc7858>. 2016, <https://www.rfc-editor.org/info/rfc7858>.
[EDNS-TCP] Wouters, P., Abley, J., Dickinson, S., and R. Bellis, "The
edns-tcp-keepalive EDNS0 Option", RFC 7828,
DOI 10.17487/RFC7828, April 2016,
<https://www.rfc-editor.org/info/rfc7828>.
[HTTP-1.1] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>.
[PRIVACY-CONS]
Wicinski, T., Ed., "DNS Privacy Considerations", RFC 9076,
DOI 10.17487/RFC9076, July 2021,
<https://www.rfc-editor.org/info/rfc9076>.
[PRIVACY-REC] [PRIVACY-REC]
Dickinson, S., Overeinder, B., van Rijswijk-Deij, R., and Dickinson, S., Overeinder, B., van Rijswijk-Deij, R., and
A. Mankin, "Recommendations for DNS Privacy Service A. Mankin, "Recommendations for DNS Privacy Service
Operators", BCP 232, RFC 8932, DOI 10.17487/RFC8932, Operators", BCP 232, RFC 8932, DOI 10.17487/RFC8932,
October 2020, <https://www.rfc-editor.org/info/rfc8932>. October 2020, <https://www.rfc-editor.org/info/rfc8932>.
[RSO_STATEMENT] [RSO_STATEMENT]
"Statement on DNS Encryption", 2021, <https://root- "Statement on DNS Encryption", 2021, <https://root-
servers.org/media/news/Statement_on_DNS_Encryption.pdf>. servers.org/media/news/Statement_on_DNS_Encryption.pdf>.
[TCP-TIMEOUT]
Kristoff, J. and D. Wessels, "DNS Transport over TCP -
Operational Requirements", Work in Progress, Internet-
Draft, draft-ietf-dnsop-dns-tcp-requirements-12, 18 August
2021, <https://www.ietf.org/archive/id/draft-ietf-dnsop-
dns-tcp-requirements-12.txt>.
[TLS-1.3] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Authors' Addresses Authors' Addresses
Paul Hoffman Paul Hoffman
ICANN ICANN
Email: paul.hoffman@icann.org Email: paul.hoffman@icann.org
Peter van Dijk Peter van Dijk
PowerDNS PowerDNS
 End of changes. 39 change blocks. 
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