Service binding and parameter specification via the DNS (DNS SVCB and HTTPS RRs)
draft-ietf-dnsop-svcb-https-04
DNSOP Working Group B. Schwartz
Internet-Draft Google
Intended status: Standards Track M. Bishop
Expires: September 18, 2021 E. Nygren
Akamai Technologies
March 17, 2021
Service binding and parameter specification via the DNS (DNS SVCB and
HTTPS RRs)
draft-ietf-dnsop-svcb-https-04
Abstract
This document specifies the "SVCB" and "HTTPS" DNS resource record
(RR) types to facilitate the lookup of information needed to make
connections to network services, such as for HTTPS origins. SVCB
records allow a service to be provided from multiple alternative
endpoints, each with associated parameters (such as transport
protocol configuration and keys for encrypting the TLS ClientHello).
They also enable aliasing of apex domains, which is not possible with
CNAME. The HTTPS RR is a variation of SVCB for HTTPS and HTTP
origins. By providing more information to the client before it
attempts to establish a connection, these records offer potential
benefits to both performance and privacy.
TO BE REMOVED: This document is being collaborated on in Github at:
https://github.com/MikeBishop/dns-alt-svc [1]. The most recent
working version of the document, open issues, etc. should all be
available there. The authors (gratefully) accept pull requests.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on September 18, 2021.
Schwartz, et al. Expires September 18, 2021 [Page 1]
Internet-Draft SVCB and HTTPS RRs for DNS March 2021
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Goals of the SVCB RR . . . . . . . . . . . . . . . . . . 5
1.2. Overview of the SVCB RR . . . . . . . . . . . . . . . . . 5
1.3. Parameter for Encrypted ClientHello . . . . . . . . . . . 6
1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
2. The SVCB record type . . . . . . . . . . . . . . . . . . . . 7
2.1. Zone file presentation format . . . . . . . . . . . . . . 8
2.2. RDATA wire format . . . . . . . . . . . . . . . . . . . . 9
2.3. SVCB query names . . . . . . . . . . . . . . . . . . . . 10
2.4. Interpretation . . . . . . . . . . . . . . . . . . . . . 10
2.4.1. SvcPriority . . . . . . . . . . . . . . . . . . . . . 11
2.4.2. AliasMode . . . . . . . . . . . . . . . . . . . . . . 11
2.4.3. ServiceMode . . . . . . . . . . . . . . . . . . . . . 12
2.5. Special handling of "." in TargetName . . . . . . . . . . 13
2.5.1. AliasMode . . . . . . . . . . . . . . . . . . . . . . 13
2.5.2. ServiceMode . . . . . . . . . . . . . . . . . . . . . 13
3. Client behavior . . . . . . . . . . . . . . . . . . . . . . . 13
3.1. Handling resolution failures . . . . . . . . . . . . . . 14
3.2. Clients using a Proxy . . . . . . . . . . . . . . . . . . 15
4. DNS Server Behavior . . . . . . . . . . . . . . . . . . . . . 15
4.1. Authoritative servers . . . . . . . . . . . . . . . . . . 15
4.2. Recursive resolvers . . . . . . . . . . . . . . . . . . . 16
4.3. General requirements . . . . . . . . . . . . . . . . . . 16
5. Performance optimizations . . . . . . . . . . . . . . . . . . 17
5.1. Optimistic pre-connection and connection reuse . . . . . 17
Show full document text