ACME IP Identifier Validation Extension
draft-ietf-acme-ip-05

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 August 18, 2019.

Copyright Notice

Copyright (c) 2019 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. HTTP Challenge
• 6. TLS with Application Level Protocol Negotiation (TLS ALPN) Challenge
• 7. DNS Challenge
• 8. IANA Considerations
• 8.1. Identifier Types
• 8.2. Challenge Types
• 9. Acknowledgments
• 10. 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 and the TLS-ALPN extension specification [I-D.ietf-acme-tls-alpn] 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 [RFC5952] Section 4 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-alpn-01” challenges from [I-D.ietf-acme-acme] Section 8.3 and [I-D.ietf-acme-tls-alpn] Section 3 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.

5. HTTP Challenge

For the “http-01” challenge the Host header MUST be set to the IP address being used for validation per [RFC7230]. The textual form of this address MUST be those defined in [RFC1123] Section 2.1 for IPv4 and in [RFC5952] Section 4 for IPv6.

6. TLS with Application Level Protocol Negotiation (TLS ALPN) Challenge

For the “tls-alpn-01” challenge the subjectAltName extension in the validation certificate MUST contain a single iPAddress which matches the address being validated. As [RFC6066] does not permit IP addresses to be used in the SNI extension HostName the server MUST instead use the IN-ADDR.ARPA [RFC1034] or IP6.ARPA [RFC3596] reverse mapping of the IP address as the HostName value instead of the literal IP address. For example if the IP address being validated is 2001:db8::1 the SNI HostName should contain “1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.”.

7. DNS Challenge

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

8. IANA Considerations

8.1. Identifier Types

Adds a new type to the Identifier list defined in Section 9.7.7 of [I-D.ietf-acme-acme] with the label “ip” and reference I-D.ietf-acme-ip.

8.2. Challenge Types

Adds the value “ip” to the Identifier Type column in the Validation Methods list defined in Section 9.7.8 of [I-D.ietf-acme-acme] for the “http-01” and “tls-alpn-01” challenges.

9. 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.

10. Normative References

Author's Address