DPRIVE WG T. Reddy
Internet-Draft McAfee
Intended status: Standards Track D. Wing
Expires: September 27, 2019
M. Richardson
Sandelman Software Works
M. Boucadair
Orange
March 26, 2019
A Bootstrapping Procedure to Discover and Authenticate DNS-over-(D)TLS
and DNS-over-HTTPS Servers
draft-reddy-dprive-bootstrap-dns-server-02
Abstract
This document specifies mechanisms to automatically bootstrap
endpoints (e.g., hosts, Customer Equipment) to discover and
authenticate DNS-over-(D)TLS and DNS-over-HTTPS servers provided by a
local network.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on September 27, 2019.
Copyright Notice
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Bootstrapping Endpoint Devices . . . . . . . . . . . . . . . 5
4. Bootstrapping IoT Devices and CPE . . . . . . . . . . . . . . 6
5. Discovery Procedure . . . . . . . . . . . . . . . . . . . . . 7
5.1. Resolution . . . . . . . . . . . . . . . . . . . . . . . 8
6. Connection handshake and service invocation . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 10
8.1. Privacy Extension Syntax . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9.1. Application Service & Application Protocol Tags . . . . . 10
9.1.1. DNS Application Service Tag Registration . . . . . . 10
9.1.2. dns.tls Application Protocol Tag Registration . . . . 11
9.1.3. dns.dtls Application Protocol Tag Registration . . . 11
9.1.4. dns.https Application Protocol Tag Registration . . . 11
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
11.1. Normative References . . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
Traditionally a caching DNS server has been provided by the local
network. This provides benefits like low latency to that DNS server
(due to its network proximity to the endpoint). However, if an
endpoint is configured to use Internet-hosted or public DNS-
over-(D)TLS [RFC7858] [RFC8094] or DNS-over-HTTPS [RFC8484] servers,
the local DNS server cannot serve the DNS requests from the
endpoints. If public DNS servers are used instead of using local DNS
servers, the operational problems are listed below:
o "Split DNS" [RFC2775] to use the special internal-only domain
names (e.g., "internal.example.com") in enterprise networks will
not work, and ".local" and "home.arpa" names cannot be locally
resolved in home networks.
o Content Delivery Networks (CDNs) that map traffic based on DNS may
lose the ability to direct end-user traffic to a nearby cluster in
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cases where a DNS service is being used that is not affiliated
with the local network and which does not send "EDNS Client
Subnet" (ECS) information [RFC7871] to the CDN's DNS authorities
[CDN].
o Some clients have pre-configured specific public DNS servers (such
as Mozilla using Cloudflare's DNS-over-HTTPS server). If
endpoints continue to use pre-configured public DNS servers, this
has a risk of relying on few centralized DNS services.
If public DNS servers are used instead of using local DNS servers,
the following paragraph discusses the impact on Network-based
security:
Various network security services are provided by Enterprise, secure
home and wall-gardened networks to protect endpoints (e.g,. Hosts,
IoT devices). [I-D.camwinget-tls-use-cases] discusses some of the
Network-based security use cases. These network security services
act on DNS requests from endpoints. However, if an endpoint is
configured to use public DNS-over-(D)TLS or DNS-over-HTTPS servers,
network security services cannot act efficiently on DNS requests from
the endpoints. In order to act on DNS requests from endpoints,
network security services can block DNS-over-(D)TLS traffic by
dropping outgoing packets to destination port 853. Identifying DNS-
over-HTTPS traffic is far more challenging than DNS-over-(D)TLS
traffic. Network security services can try to identify the domains
offering DNS-over-HTTPS servers, and DNS-over-HTTPS traffic can be
blocked by dropping outgoing packets to these domains. If the
endpoint has enabled strict privacy profile (Section 5 of [RFC8310]),
and the network security service blocks the traffic to the public DNS
server, DNS service is not available to the endpoint and ultimately
the endpoint cannot access Internet. If the endpoint has enabled
opportunistic privacy profile (Section 5 of [RFC8310]), and the
network security service blocks traffic to the public DNS server, the
endpoint will either fallback to an encrypted connection without
authenticating the DNS server provided by the local network or
fallback to clear text DNS, and cannot exchange encrypted DNS
messages.
If the network security service fails to block DNS-over-(D)TLS or
DNS-over-HTTPS traffic, this can compromise the endpoint security;
some of the potential security threats are listed below:
o The network security service cannot prevent an endpoint from
accessing malicious domains.
o If the endpoint is an IoT device which is configured to use public
DNS-over-(D)TLS or DNS-over-HTTPS servers, and if a policy
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enforcement point in the local network is programmed using a
Manufacturer Usage Description (MUD) file [I-D.ietf-opsawg-mud] by
a MUD manager to only allow intented communications to and from
the IoT device, the policy enforcement point cannot enforce the
Network Access Control List rules based on domain names (Section 8
of [I-D.ietf-opsawg-mud]).
If the network security service sucessfully blocks DNS-over-(D)TLS
and DNS-over-HTTPS traffic, this can still compromise the endpoint
security and privacy; some of the potential security threats are
listed below:
o Pervasive monitoring of DNS traffic.
o An internal attacker can modify the DNS responses to re-direct the
client to incorrect and malicious servers.
To overcome the above threats, the document proposes a mechanism to
automatically bootstrap the endpoints to discover and authenticate
the DNS-over-(D)TLS and DNS-over-HTTPS servers provided by the local
network. The overall procedure can be structured into the following
steps:
o Bootstrapping phase (Section 3 and Section 4) is meant to
automatically bootstrap endpoints with local network's CA
certificates and DNS server certificate.
o Discovery phase (Section 5) is meant to discover the privacy-
enabling protocols supported by the DNS server and usable DNS
server IP addresses and port numbers.
o Connection handshake and service invocation: The DNS client
initiates (D)TLS handshake with the DNS server learned in the
discovery phase. Furthermore, DNS client uses the credentials
discovered during the bootstrapping phase to validate the server
certificate.
Note: The strict and opportunistic privacy profiles as defined in
[RFC8310] only applies to DNS-over-(D)TLS protocols, there has been
no such distinction made for DNS-over-HTTPS protocol.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here.
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(D)TLS is used for statements that apply to both Transport Layer
Security [RFC8446] and Datagram Transport Layer Security [RFC6347].
Specific terms are used for any statement that applies to either
protocol alone.
This document uses the terms defined in [RFC8499].
3. Bootstrapping Endpoint Devices
The following steps explain the mechanism to automatically bootstrap
an endpoint with the local network's CA certificates and DNS server
certificate:
1. The endpoint authenticates to the local network and discovers the
EST server using DNS-based Service Discovery [RFC6763].
2. The endpoint establishes provisional TLS connection with the EST
server, i.e. the endpoint provisionally accepts the unverified
TLS server certificate. However, the endpoint MUST authenticate
the EST server before it can accept the CA certificates. The
endpoint either uses Secure Remote Password protocol (SRP)
[SRP-6] as an authentication method for the Transport Layer
Security protocol [RFC5054] or uses the mutual authentication
scheme discussed in [RFC8120] to authenticate the discovered EST
server. SRP is an authentication method that allows the use of
usernames and passwords over unencrypted channels without
revealing the password to an eavesdropper. Similarty, the mutual
authentication scheme is based on password-based authenticated
key exchange (PAKE) and provides mutual authentication between a
HTTP client and an HTTP server using username and password as
credentials.
3. If the EST server authentication is successful, the endpoint
requests the full EST distribution of current CA certificates and
validates the EST server certificate. If the EST server
certificate cannot be verified using the CA certificates
downloaded, the TLS connection is immediately discarded and the
endpoint abandons the attempt to bootstrap from the EST server
and discards the CA certificates conveyed by the EST server. If
the EST server certificate is verified using the CA certificates
downloaded, the endpoint stores the CA certificates as Explicit
Trust Anchor database entries. The endpoint uses the Explicit
Trust Anchor database to validate the DNS server certificate.
The endpoint needs to perform SCRAM authentication the first time
it connects EST server. On subsequent connections to the EST
server, the endpoint can validate the EST server certificate
using the Explicit Trust Anchor database.
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4. The endpoint learns the End-Entity certificates [RFC8295] from
the EST server. The certificate provisioned to the DNS server in
the local network will be treated as a End-Entity certificate.
The endpoint needs to identify the certificate provisioned to the
DNS server. The SRV-ID identifier type [RFC6125] within
subjectAltName entry can be used to identify the DNS server
certificate. For example, DNS server certificate will include
SRV-ID "_domain-s.example.net" along with DNS-ID "example.net".
This specification defines SRV service label "domain-s" in
Section 9. As a reminder, the protocol component is not included
in the SRV-ID [RFC4985].
4. Bootstrapping IoT Devices and CPE
The following steps explain the mechanism to automatically bootstrap
IoT devices with local network's CA certificates and DNS server
certificate. The below steps can also be used by CPE acting as DNS
forwarder to discover and authenticate DNS-over-(D)TLS and DNS-over-
HTTPS servers provided by the access network.
o Bootstrapping Remote Secure Key Infrastructures (BRSKI) discussed
in [I-D.ietf-anima-bootstrapping-keyinfra] provides a solution for
secure automated bootstrap of devices. BRSKI specifies means to
provision credentials on devices to be used to operationally
access networks. In addition, BRSKI provides an automated
mechanism for the bootstrap distribution of CA certificates from
the EST server. The IoT device can use BRSKI to automatically
bootstrap the IoT device using the IoT manufacturer provisioned
X.509 certificate, in combination with a registrar provided by the
local network and IoT device manufacturer's authorizing service
(MASA).
1. The IoT device authenticates to the local network using the
IoT manufacturer provisioned X.509 certificate. The IoT
device can request and get a voucher from the MASA service via
the registrar. The voucher is signed by the MASA service and
includes the local network's CA public key.
2. The IoT device validates the signed voucher using the
manufacturer installed trust anchor associated with the MASA,
stores the CA's public key and validates the provisional TLS
connection to the registrar.
3. The IoT device requests the full Enrollment over Secure
Transport (EST) [RFC7030] distribution of current CA
certificates (Section 5.9.1 in
[I-D.ietf-anima-bootstrapping-keyinfra]) from the registrar
operating as a BRSKI-EST server. The IoT devices stores the
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CA certificates as Explicit Trust Anchor database entries.
The IoT device uses the Explicit Trust Anchor database to
validate the DNS server certificate.
4. The IoT device learns the End-Entity certificates [RFC8295]
from the BRSKI-EST server. The certificate provisioned to the
DNS server in the local network will be treated as a End-
Entity certificate. The IoT device needs to identify the
certificate provisioned to the DNS server. The SRV-ID
identifier type [RFC6125] within subjectAltName entry can be
used to identify the DNS server certificate. For example, DNS
server certificate will include SRV-ID "_domain-s.example.net"
along with DNS-ID "example.net". This specification defines
SRV service label "domain-s" in Section 9. As a reminder, the
protocol component is not included in the SRV-ID [RFC4985].
5. Discovery Procedure
A DNS client discovers the DNS server in the local network supporting
DNS-over-TLS, DNS-over-DTLS and DNS-over-HTTPS protocols by using the
following discovery mechanism:
o The DNS client retrieves the authentication domain name for the
DNS server from the DNS-ID identifier type within subjectAltName
entry in the DNS server certificate.
o The DNS client then uses the authentication domain name for
S-NAPTR [RFC3958] lookup to learn the protocols DNS-over-TLS, DNS-
over-DTLS, and DNS-over-HTTPS supported by the DNS server and the
DNS privacy protocol preferred by the DNS server administrators,
as specified in Section 5.1 and Section 9.1. This specification
adds a SRV service label "domain-s" for privacy-enabling DNS
servers. In the example below, for authentication domain name
'example.net', the resolution algorithm will result in the
privacy-enabling protocols supported by the DNS server and usable
DNS server IP addresses and port numbers.
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example.net.
IN NAPTR 100 10 "" DPRIVE:dns.tls "" dns1.example.net.
IN NAPTR 200 10 "" DPRIVE:dns.dtls "" dns2.example.net.
dns1.example.net.
IN NAPTR 100 10 S DPRIVE:dns.tls "" _domain-s._tcp.example.net.
dns2.example.net.
IN NAPTR 100 10 S DPRIVE:dns.dtls "" _domain-s._udp.example.net.
_domain-s._tcp.example.net.
IN SRV 0 0 853 a.example.net.
_domain-s._udp.example.net.
IN SRV 0 0 853 a.example.net.
a.example.net.
IN A 192.0.2.1
IN AAAA 2001:db8:8:4::2
Figure 1
o If DNS-over-HTTPS protocol is supported by the DNS server, the DNS
client finds the URI template of the DNS-over-HTTPS server using
one of the mechanisms discussed in
[I-D.ietf-doh-resolver-associated-doh] to use the https URI scheme
(Section 3 of [RFC8484]).
5.1. Resolution
Once the DNS client has retrieved the authentication domain name for
the DNS server, an S-NAPTR lookup with 'DPRIVE' application service
and the desired protocol tag is made to obtain information necessary
to securely connect to the DNS server. The S-NAPTR lookup is
performed using an recursive DNS resolver discovered from an
untrusted source (such as DHCP).
This specification defines "DPRIVE" as an application service tag
(Section 9.1.1) and "dns.tls" (Section 9.1.2), "dns.dtls"
(Section 9.1.3), and "dns.https" (Section 9.1.4) as application
protocol tags.
If no DNS-specific S-NAPTR records can be retrieved, the discovery
procedure fails for this authentication domain name. However, before
retrying a lookup that has failed, a DNS client MUST wait a time
period that is appropriate for the encountered error (e.g., NXDOMAIN,
timeout, etc.).
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6. Connection handshake and service invocation
The DNS client initiates (D)TLS handshake with the DNS server, the
server presents its certificate in ServerHello message, and the DNS
client matches the DNS server certificate downloaded in step 4 in
Section 3 and Section 4 with the certificate provided by the DNS
server in (D)TLS handshake. If the match is successful, the DNS
client validates the server certificate using the Explicit Trust
Anchor database entries downloaded in step 3 in Section 3 and
Section 4.
If the match is successful and server certificate is successfully
validated, the client continues with the connection as normal.
Otherwise, the client MUST treat the server certificate validation
failure as a non-recoverable error. If the DNS client cannot reach
or establish an authenticated and encrypted connection with the
privacy-enabling DNS server provided by the local network, the DNS
client can fallback to the privacy-enabling public DNS server.
7. Security Considerations
The bootstrapping procedure to discover and authenticate DNS-
over-(D)TLS and DNS-over-HTTPS Servers MUST be enabled by the
endpoint in a trusted network (e.g. Enterprise, Secure home
networks) and disabled in a untrusted network (e.g. Public WiFi
network), similar to the way VPN connection from the endpoint to a
VPN gateway is disconnected in a trusted network and VPN connection
is established in a untrusted network.
If the endpoint has enabled strict privacy profile, and the network
security service blocks the traffic to the privacy-enabling public
DNS server, a hard failure occurs and the user is notified. The user
has a choice to switch to another network or if the user trusts the
network, the user can enable strict privacy profile with the DNS-
over-(D)TLS or DNS-over-HTTPS server discovered in the network
instead of downgrading to opportunistic privacy profile.
The primary attacks against the methods described in Section 5 are
the ones that would lead to impersonation of a DNS server and
spoofing the DNS response to indicate that the DNS server does not
support any privacy-enabling protocols. To protect against DNS-
vectored attacks, secured DNS (DNSSEC) can be used to ensure the
validity of the DNS records received. The explicit trust anchor
database entries downloaded in step 3 in Section 3 and Section 4 can
be used by the endpoint to validate the DNSSEC signature.
Impersonation of the DNS server is prevented by validating the
certificate presented by the DNS server. If the BRSKI-EST server
conveys the DNS server certificate, but the S-NAPTR lookup indicates
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that the DNS server does not support any privacy-enabling protocols,
the client can detect the DNS response is spoofed.
Security considerations in [I-D.ietf-anima-bootstrapping-keyinfra],
[RFC5054] and [RFC8120] need to be taken into consideration.
8. Privacy Considerations
[RFC7626] discusses DNS privacy considerations in both "on the wire"
(Section 2.4 of [RFC7626]) and "in the server" (Section 2.5 of
[RFC7626] contexts. The endpoint may not know if the DNS-over-(D)TLS
or DNS-over-HTTPS server in the local network has a privacy
preserving data policy. A new privacy certificate extension is
defined that identifies the privacy preserving data policy of the DNS
server. The extension contains a URL that points to the privacy
preserving data policy.
8.1. Privacy Extension Syntax
The syntax for the privacy extension is:
Privacy ::= CHOICE {
none NULL, -- No privacy policy provided
pURL PrivacyURL } -- Privacy preserving data policy
PrivacyURL ::= IA5String -- MUST use https scheme
9. IANA Considerations
IANA is requested to allocate the SRV service name of "domain-s" for
DNS-over-(D)TLS and DNS-over-HTTPS.
9.1. Application Service & Application Protocol Tags
This document requests IANA to make the following allocations from
the registry available at: https://www.iana.org/assignments/s-naptr-
parameters/s-naptr-parameters.xhtml.
9.1.1. DNS Application Service Tag Registration
o Application Protocol Tag: DPRIVE
o Intended Usage: See Section 5.1
o Security Considerations: See Section 7
o Contact Information: <one of the authors>
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9.1.2. dns.tls Application Protocol Tag Registration
o Application Protocol Tag: dns.tls
o Intended Usage: See Section 5.1
o Security Considerations: See Section 7
o Contact Information: <one of the authors>
9.1.3. dns.dtls Application Protocol Tag Registration
o Application Protocol Tag: dns.dtls
o Intended Usage: See Section 5.1
o Security Considerations: See Section 7
o Contact Information: <one of the authors>
9.1.4. dns.https Application Protocol Tag Registration
o Application Protocol Tag: dnshttps
o Intended Usage: See Section 5.1
o Security Considerations: See Section 7
o Contact Information: <one of the authors>
10. Acknowledgments
Thanks to Joe Hildebrand, Harsha Joshi, Shashank Jain, Patrick
McManus, Eliot Lear and Sara Dickinson for the discussion and
comments.
11. References
11.1. Normative References
[I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Behringer, M., Bjarnason,
S., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-19 (work in progress), March 2019.
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[I-D.ietf-doh-resolver-associated-doh]
Hoffman, P., "Associating a DoH Server with a Resolver",
draft-ietf-doh-resolver-associated-doh-03 (work in
progress), March 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3958] Daigle, L. and A. Newton, "Domain-Based Application
Service Location Using SRV RRs and the Dynamic Delegation
Discovery Service (DDDS)", RFC 3958, DOI 10.17487/RFC3958,
January 2005, <https://www.rfc-editor.org/info/rfc3958>.
[RFC4985] Santesson, S., "Internet X.509 Public Key Infrastructure
Subject Alternative Name for Expression of Service Name",
RFC 4985, DOI 10.17487/RFC4985, August 2007,
<https://www.rfc-editor.org/info/rfc4985>.
[RFC5054] Taylor, D., Wu, T., Mavrogiannopoulos, N., and T. Perrin,
"Using the Secure Remote Password (SRP) Protocol for TLS
Authentication", RFC 5054, DOI 10.17487/RFC5054, November
2007, <https://www.rfc-editor.org/info/rfc5054>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
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[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "Specification for DNS over Transport
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
2016, <https://www.rfc-editor.org/info/rfc7858>.
[RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram
Transport Layer Security (DTLS)", RFC 8094,
DOI 10.17487/RFC8094, February 2017,
<https://www.rfc-editor.org/info/rfc8094>.
[RFC8120] Oiwa, Y., Watanabe, H., Takagi, H., Maeda, K., Hayashi,
T., and Y. Ioku, "Mutual Authentication Protocol for
HTTP", RFC 8120, DOI 10.17487/RFC8120, April 2017,
<https://www.rfc-editor.org/info/rfc8120>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8295] Turner, S., "EST (Enrollment over Secure Transport)
Extensions", RFC 8295, DOI 10.17487/RFC8295, January 2018,
<https://www.rfc-editor.org/info/rfc8295>.
[RFC8446] 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>.
[RFC8484] 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>.
[RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/info/rfc8499>.
11.2. Informative References
[CDN] "End-User Mapping: Next Generation Request Routing for
Content Delivery", 2015,
<https://conferences.sigcomm.org/sigcomm/2015/pdf/papers/
p167.pdf>.
[I-D.camwinget-tls-use-cases]
Andreasen, F., Cam-Winget, N., and E. Wang, "TLS 1.3
Impact on Network-Based Security", draft-camwinget-tls-
use-cases-04 (work in progress), March 2019.
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[I-D.ietf-opsawg-mud]
Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
Description Specification", draft-ietf-opsawg-mud-25 (work
in progress), June 2018.
[RFC2775] Carpenter, B., "Internet Transparency", RFC 2775,
DOI 10.17487/RFC2775, February 2000,
<https://www.rfc-editor.org/info/rfc2775>.
[RFC7626] Bortzmeyer, S., "DNS Privacy Considerations", RFC 7626,
DOI 10.17487/RFC7626, August 2015,
<https://www.rfc-editor.org/info/rfc7626>.
[RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W.
Kumari, "Client Subnet in DNS Queries", RFC 7871,
DOI 10.17487/RFC7871, May 2016,
<https://www.rfc-editor.org/info/rfc7871>.
[RFC8310] Dickinson, S., Gillmor, D., and T. Reddy, "Usage Profiles
for DNS over TLS and DNS over DTLS", RFC 8310,
DOI 10.17487/RFC8310, March 2018,
<https://www.rfc-editor.org/info/rfc8310>.
[SRP-6] "SRP-6: Improvements and Refinements to the Secure Remote
Password Protocol", October 2002,
<http://grouper.ieee.org/groups/1363/>.
Authors' Addresses
Tirumaleswar Reddy
McAfee, Inc.
Embassy Golf Link Business Park
Bangalore, Karnataka 560071
India
Email: kondtir@gmail.com
Dan Wing
USA
Email: dan@danwing.org
Reddy, et al. Expires September 27, 2019 [Page 14]
Internet-Draft DoT/DoH server discovery March 2019
Michael C. Richardson
Sandelman Software Works
USA
Email: mcr+ietf@sandelman.ca
Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Reddy, et al. Expires September 27, 2019 [Page 15]