Internet-Draft | DNSSEC automation | February 2021 |
Wisser & Huque | Expires 23 August 2021 | [Page] |
- Workgroup:
- Domain Name System Operations (dnsop)
- Published:
- Intended Status:
- Standards Track
- Expires:
DNSSEC automation
Abstract
This document describes an algorithm and a protocol to automate DNSSEC multi-signer [RFC8901] "Multi-Signer DNSSEC Models" setup, operations and decomissioning. It makes use of [RFC8078] "Managing DS Records from the Parent via CDS/CDNSKEY" and [RFC7477] "Child-to-Parent Synchronization in DNS" to accomplish this.¶
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/.¶
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This Internet-Draft will expire on 23 August 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.¶
1. Introduction
[RFC8901] describes the neccessary steps and API for a multi-signer DNSSEC configuration. In this document we will combine [RFC8901] with [RFC8078] and [RFC7477] to define a fully automatable algorithm for setting up, operating and decomissioning of a multi-signer DNSSEC configuration.¶
One of the special cases of multi-signer DNSSEC is actually the secure change of DNS operator.¶
1.1. Out-Of-Scope
In order for any multi-signer group to give consitent answers over all instances the contents of the zone have to be synchronized. The content synchronization is out-of-scope for this document.¶
1.2. Notation
Short definitions of expressions used in this document¶
1.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].¶
2. Use Cases
2.1. Running a multi-signer setup
As described in [RFC8901] a multi-signer DNSSEC configuration has some challenges that can be overcome with the right infrastructure and following a number of steps for setup and operation.¶
In this document we describe how all of the steps in the multi-signer DNSSEC setup can be automated. That is, all except the initial trust between involded signers.¶
2.2. Secure change of name server operator
Changing the name server operator of a DNSSEC signed zone can be quite a challenge. Currently the most used algorithm is "going insecure". This is a bad choice for security. And a bad choice for users relying on the security of the zone.¶
Changing name server operators is a special case of multi-signer DNSSEC operations. It simply comes down to the new operator joins the old operator in a multi-signer setup. And once that is completed the old operator leaves the multi-signer setup.¶
3. Algorithm
3.1. Setting up a new multi-signer group
The zone is already authoritatively served by one DNS operator and is DNSSEC signed. For full automation both the KSK and ZSK or CSK must be online.¶
This would be a special case, a multi-signer group with only one signer.¶
3.2. Configuration
The following configrations have to be made for any signer of the multi-signer group before joining the group. These steps are not automated by this draft.¶
3.3. A new signer joins the multi-signer group
3.3.1. Prerequisites
The new signer¶
3.3.2. Steps for joining
- a new signer joins the group¶
- Exchange of keys, after this step all signers must have the dnskey set of all other signers of the group¶
- Calculate CDS/CDNSKEY set¶
- All signers put the ZSK of all other signers in their DNSKEY set.¶
- All signers publish their CDS/CDNSKEY set¶
- Wait for parent to pick up DS updates¶
- Remove CDS/CDNSKEY set from all signers¶
- Wait 2 time maximum TTL of DS at parent and DNSKEY at all children¶
- Exchange of NS set, after this step all signers must have the ns set of all other signers¶
- Compile new complete NS set with NS records from all signers¶
- Compare to NS set at parent¶
- If parent if different, publish CSYNC record with NS and A and AAAA bit set.¶
- Wait for parent to pick up changes¶
- Remove CSYNC record from all signers¶
3.4. A signer leaves the multi-signer group
- Signal to all other signers to remove the leaving signes NS records¶
- Compile new complete NS set with NS records from all signers¶
- Compare to NS set at parent¶
- If parent if different, publish CSYNC record with NS and A and AAAA bit set.¶
- Wait for parent to pick up changes¶
- Remove CSYNC record from all signers¶
- Wait 2 times TTL of maximum NS TTL from parent and all signers¶
- Signal all other signers leaving of multi-signer group¶
- Stop answering queries¶
- Remaining signers remove ZSK of leaving signer from their DNSKEY set¶
- Remaining signers recalculat DNSKEY set¶
- Calculate CDS/CDNSKEY set¶
- All signers put the ZSK of all other signers in their DNSKEY set.¶
- All signers publish their CDS/CDNSKEY set¶
- Wait for parent to pick up DS updates¶
- Remove CDS/CDNSKEY set from all signers¶
4. Automation
Automation of the neccessary steps described in the last section can be devided into two main models, centralized and decentralized. Both have pros and cons and any zone operator should chose wisely.¶
4.1. Centralized
In a centralized model the zone operator will run a software that executes all steps neccessary and controls all signers.¶
4.2. Decentralized
In the decentralized models all signers will comminucate with each other and execute the necessary steps on their instance only. For this signers need a specialised protocol to comminicate configuration details that are not part of the zone data.¶
8. Normative References
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC7477]
- Hardaker, W., "Child-to-Parent Synchronization in DNS", RFC 7477, DOI 10.17487/RFC7477, , <https://www.rfc-editor.org/info/rfc7477>.
- [RFC8078]
- Gudmundsson, O. and P. Wouters, "Managing DS Records from the Parent via CDS/CDNSKEY", RFC 8078, DOI 10.17487/RFC8078, , <https://www.rfc-editor.org/info/rfc8078>.
9. Informative References
- [RFC8901]
- Huque, S., Aras, P., Dickinson, J., Vcelak, J., and D. Blacka, "Multi-Signer DNSSEC Models", RFC 8901, DOI 10.17487/RFC8901, , <https://www.rfc-editor.org/info/rfc8901>.