Split-Horizon DNS Configuration in Enterprise Networks
draft-reddy-add-enterprise-split-dns-00
ADD T. Reddy
Internet-Draft McAfee
Intended status: Standards Track D. Wing
Expires: August 24, 2021 Citrix
February 20, 2021
Split-Horizon DNS Configuration in Enterprise Networks
draft-reddy-add-enterprise-split-dns-00
Abstract
When split-horizon DNS is deployed by an enterprise, certain
enterprise domains are only resolvable by querying the network-
provided DNS server. DNS clients which use DNS servers not provided
by the network need to route those DNS domain queries to the network-
provided DNS server. This document informs DNS clients of split-
horizon DNS, their DNS domains, and is compatible with encrypted DNS.
Status of This Memo
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This Internet-Draft will expire on August 24, 2021.
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Internet-Draft Split-Horizon DNS Configuration February 2021
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Scope of the Document . . . . . . . . . . . . . . . . . . . . 4
4. Split DNS . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. PvD dnsZones . . . . . . . . . . . . . . . . . . . . . . . . 6
6. PvD SplitDNSAllowed Key . . . . . . . . . . . . . . . . . . . 7
7. An Example . . . . . . . . . . . . . . . . . . . . . . . . . 7
8. Roaming Enterprise Users . . . . . . . . . . . . . . . . . . 8
9. Upstream Encryption . . . . . . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 9
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
13.1. Normative References . . . . . . . . . . . . . . . . . . 9
13.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
Historically, an endpoint would utilize network-provided DNS servers
upon joining a network (e.g., DHCP OFFER, IPv6 Router Advertisement).
While it has long been possible to configure endpoints to ignore the
network's suggestions and use a (public) DNS server on the Internet,
this was seldom used because some networks block UDP/53 (in order to
enforce their own DNS policies). With the advent of DoT and DoH,
such network blocking is more difficult, but the endpoint is unable
to (properly) resolve split-horizon DNS domains which must query the
network-provided DNS server.
[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. Also, there has been an increase in the
availability of "public resolvers" [RFC8499] which DNS clients may be
pre-configured to use instead of the default network resolver for a
variety of reasons (e.g., offer a good reachability, support an
encrypted transport, provide a claimed privacy policy, (lack of)
filtering).
If public encrypted DNS servers (e.g., DNS-over-TLS (DoT) [RFC7858]
or DNS-over-HTTPS (DoH) [RFC8484]) are used instead of using local
DNS servers, it can adversely impact Enterprise network-based
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