ACME IP Identifier Validation Extension
draft-ietf-acme-ip-02

Abstract

This document specifies identifiers and challenges required to enable the Automated Certificate Management Environment (ACME) to issue certificates for IP addresses.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on November 19, 2018.

Copyright Notice

Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. Terminology
• 3. IP Identifier
• 4. Identifier Validation Challenges
• 5. IANA Considerations
• 5.1. Identifier Types
• 5.2. Challenge Types
• 6. Security Considerations
• 7. Acknowledgments
• 8. Normative References
• Author's Address

1. Introduction

The Automatic Certificate Management Environment (ACME) [I-D.ietf-acme-acme] only defines challenges for validating control of DNS host name identifiers which limits its use to being used for issuing certificates for DNS identifiers. In order to allow validation of IPv4 and IPv6 identifiers for inclusion in X.509 certificates this document specifies how challenges defined in the original ACME specification can be used to validate IP identifiers.

2. Terminology

In this document, the key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” are to be interpreted as described in BCP 14, [RFC2119].

3. IP Identifier

[I-D.ietf-acme-acme] only defines the identifier type “dns” which is used to refer to fully qualified domain names. If a ACME server wishes to request proof that a user controls a IPv4 or IPv6 address it MUST create an authorization with the identifier type “ip”. The value field of the identifier MUST contain the textual form of the address as defined in [RFC1123] Section 2.1 for IPv4 and in [RFC4291] Section 2.2 for IPv6.

An identifier for the IPv6 address 2001:db8::1 would be formatted like so:

{"type": "ip", "value": "2001:db8::1"}

4. Identifier Validation Challenges

IP identifiers MAY be used with the existing “http-01” and “tls-sni-02” challenges from [I-D.ietf-acme-acme] Sections 8.3 and 8.4 respectively. To use IP identifiers with these challenges their initial DNS resolution step MUST be skipped and the IP address used for validation MUST be the value of the identifier. For the “http-01” challenge the Host header MUST be set to the IP address being used for validation per [RFC7230].

The existing “dns-01” challenge MUST NOT be used to validate IP identifiers.

5. IANA Considerations

5.1. Identifier Types

Adds a new type to the Identifier list defined in Section 9.7.5 of [I-D.ietf-acme-acme] with the label “ip” and reference I-D.ietf-acme-ip.

5.2. Challenge Types

Add the value “ip” to the identifier type column for the “http-01” and “tls-sni-02” challenges.

6. Security Considerations

Given the often short delegation periods for IP addresses provided by various service providers CAs MAY want to impose shorter lifetimes for certificates which contain IP identifiers. They MAY also impose restrictions on IP identifiers which are in CIDRs known to be assigned to service providers who dynamically assign addresses to users for indeterminate periods of time.

7. Acknowledgments

The author would like to thank those who contributed to this document and offered editorial and technical input, especially Jacob Hoffman-Andrews and Daniel McCarney.

8. Normative References

Author's Address