Automated Certificate Management Environment (ACME) Service Discovery
draft-tweedale-acme-discovery-01

Document Type Active Internet-Draft (individual)
Author Fraser Tweedale 
Last updated 2020-11-16
Stream (None)
Intended RFC status (None)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                        F. Tweedale
Internet-Draft                                                   Red Hat
Intended status: Standards Track                        16 November 2020
Expires: 20 May 2021

 Automated Certificate Management Environment (ACME) Service Discovery
                    draft-tweedale-acme-discovery-01

Abstract

   This document specifies a DNS-based Service Discovery (DNS-SD)
   profile that enables Automated Certificate Management Environment
   (ACME) clients to locate ACME servers in their network environment.

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 20 May 2021.

Copyright Notice

   Copyright (c) 2020 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.

Tweedale                   Expires 20 May 2021                  [Page 1]
Internet-Draft                   ACME-SD                   November 2020

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  DNS-SD Profile  . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Service Instance Name . . . . . . . . . . . . . . . . . .   3
     3.2.  PTR Records (Service Instance Enumeration)  . . . . . . .   3
     3.3.  SRV Records . . . . . . . . . . . . . . . . . . . . . . .   4
     3.4.  TXT Records . . . . . . . . . . . . . . . . . . . . . . .   4
       3.4.1.  "path" attribute (ACME Directory Path)  . . . . . . .   4
       3.4.2.  "i" attribute (ACME Identifier Types) . . . . . . . .   5
       3.4.3.  "v" attribute (ACME Validation Methods) . . . . . . .   5
     3.5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Client Behaviour  . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  When to Perform Service Discovery . . . . . . . . . . . .   6
     4.2.  Candidate Parent Domains  . . . . . . . . . . . . . . . .   7
     4.3.  DNS-SD Queries and Validation . . . . . . . . . . . . . .   7
       4.3.1.  Service Instance Enumeration  . . . . . . . . . . . .   7
       4.3.2.  Service Instance Resolution . . . . . . . . . . . . .   8
       4.3.3.  Verifying the Server  . . . . . . . . . . . . . . . .   8
     4.4.  ACME Operations . . . . . . . . . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     5.1.  "acme-server" Service Name Registration . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
     6.1.  TLS and Certificate Validation  . . . . . . . . . . . . .  10
     6.2.  Parent Domain Selection . . . . . . . . . . . . . . . . .  10
     6.3.  DNS Security  . . . . . . . . . . . . . . . . . . . . . .  11
     6.4.  Service Instance Delegation . . . . . . . . . . . . . . .  12
     6.5.  Multicast DNS . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  13
   8.  Informative References  . . . . . . . . . . . . . . . . . . .  14
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   Automatic Certificate Management Environment [ACME] specifies a
   protocol by which a client may, in an automatable way, prove control
   of identifiers and obtain a certificate from an Certificate Authority
   (the ACME server).  However, it did not specify a mechanism by which
   a client can locate a suitable ACME server.  It is assumed that a
   client will be configured to use a particular ACME server, or else
   default to some well known, publicly accessible ACME service.

   In some environments, such as corporate networks, it may be
   impossible for ACME clients to obtain certificates from a publicly
Show full document text