DoH Preference Hints for HTTP
draft-schinazi-httpbis-doh-preference-hints-02
Network Working Group D. Schinazi
Internet-Draft Google LLC
Intended status: Experimental N. Sullivan
Expires: 14 January 2021 J. Kipp
Cloudflare
13 July 2020
DoH Preference Hints for HTTP
draft-schinazi-httpbis-doh-preference-hints-02
Abstract
When using a publicly available DNS-over-HTTPS (DoH) server, some
clients may suffer poor performance when the authoritative DNS server
is located far from the DoH server. For example, a publicly
available DoH server provided by a Content Delivery Network (CDN)
should be able to resolve names hosted by that CDN with good
performance but might take longer to resolve names provided by other
CDNs, or might provide suboptimal results if that CDN is using DNS-
based load balancing and returns different address records depending
or where the DNS query originated from. This document attempts to
lessen these issues by allowing the web server to indicate to the
client which DoH server can best resolve its addresses. This
document defines an HTTP header field that enables web host operators
to inform user agents of the preferred DoH servers to use for
subsequent DNS lookups for the host's domain.
Discussion of this work is encouraged to happen on the ADD IETF
mailing list add@ietf.org or on the GitHub repository which contains
the draft: https://github.com/DavidSchinazi/draft-httpbis-doh-
preference-hints.
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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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Schinazi, et al. Expires 14 January 2021 [Page 1]
Internet-Draft DoH Preference Hints July 2020
This Internet-Draft will expire on 14 January 2021.
Copyright Notice
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document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions and Definitions . . . . . . . . . . . . . . . 3
2. The DoH-Preference Header Field . . . . . . . . . . . . . . . 3
2.1. The max-age Directive . . . . . . . . . . . . . . . . . . 4
2.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Considerations For Choosing a Preferred DoH Server . . . 4
4. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Fallback . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Internationalization Considerations . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
When using a publicly available DNS-over-HTTPS (DoH) server, some
clients may suffer poor performance when the authoritative DNS server
is located far from the DoH server. For example, a publicly
available DoH server provided by a Content Delivery Network (CDN)
should be able to resolve names hosted by that CDN with good
performance but might take longer to resolve names provided by other
CDNs, or might provide suboptimal results if that CDN is using DNS-
based load balancing and returns different address records depending
or where the DNS query originated from. This document attempts to
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