| Internet-Draft | DNSSEC | March 2022 |
| Hoffman | Expires 20 September 2022 | [Page] |
This document describes the DNS security extensions (commonly called "DNSSEC") that are specified RFCs 4033, 4034, 4035, and a handful of others. The purpose is to introduce all of the RFCs in one place so that the reader can understand the many aspects of DNSSEC. This document does not update any of those RFCs.¶
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The core specification for what we know as DNSSEC (the combination of [RFC4033], [RFC4034], and [RFC4035]) describes a set of protocols that provides origin authentication to data in the DNS. [RFC6840] updates and extends those core RFCs, but does not fundamentally change the way that DNSSEC works.¶
This document lists many (but not all) of the RFCs that should be considered by someone creating an implementation of, or someone deploying, modern DNSSEC. It uses terminology from those documents without defining that terminology. It also points to the relevant IANA registries that relate to DNSSEC. It does not, however, point to standards that rely on zones needing to be signed by DNSSEC.¶
The DNSSEC set of protocols is widely considered the best current practice for adding origin authentication of data in the DNS. To date, no standards-track RFCs offer any other method for such origin authentication of data in the DNS.¶
Some observers note that, more than 15 years after the DNSSEC specification was published, it is still not widely deployed. Recent estimates are that fewer than 10% of the domain names used for web sites are signed, and only around a third of queries to recursive resolvers are validated. However, this low level of implementation does not affect whether DNSSEC is a best current practice; it just indicates that the value of deploying DNSSEC is often considered lower than the cost.¶
What we today call "DNSSEC" is formally version 3 of the DNSSEC specification. However, earlier versions of DNSSEC were thinly deployed and significantly less visible than the current DNSSEC specification. Throughout this document, "DNSSEC" means the version of the protocol initially defined in [RFC4033], [RFC4034], and [RFC4035].¶
The three initial core documents generally cover different topics:¶
At the time this set of core documents was published, someone could create a DNSSEC implementation of signing software, of an DNSSEC-aware authoritative server, and/or a DNSSEC-aware recursive resolver from the three core documents plus a few older RFCs specifying the cryptography used. Those two older documents are:¶
As with any major protocol, developers and operators discovered issues with the original core documents over the years. [RFC6840] is an omnibus update to the original core documents and thus itself has become a core document. In addition to covering new requirements from new DNSSEC RFCs, it describes many important security and interoperability issues that arose during the deployment of the initial specifications, particularly after the DNS root was signed in 2010. It also lists some errors in the examples of the core specifications.¶
[RFC6840] brings a few additions into the core of DNSSEC. It makes NSEC3 [RFC5155] as much a part of DNSSEC as NSEC is. It also makes the SHA-2 hash function defined in [RFC4509] and [RFC5702] part of the core as well. # Cryptographic Algorithms and DNSSEC¶
Cryptography improves over time, and new algorithms get adopted by various Internet protocols. Two new signing algorithms have been adopted by the DNSSEC community: ECDSA [RFC6605] and EdDSA [RFC8080]. The GOST signing algorithm [RFC5933] was also adopted, but has seen very limited use, likely because it is a national algorithm specific to a very small number of countries.¶
Implementation developers who want to know which algorithms to implement in DNSSEC software should refer to [RFC8624]. Note that this specification is only about what algorithms should and should not be included in implementations: it is not advice for which algorithms that zone operators should and should not sign with, nor which algorithms recursive resolver operators should or should not validate.¶
The DNSSEC community has extended the DNSSEC core and the cryptographic algorithms both in terms of describing good operational practices and in new protocols. Some of the RFCs that describe these extensions include:¶
IANA already has two registries that relate to DNSSEC: DNSSEC algorithm numbers (https://www.iana.org/assignments/dns-sec-alg-numbers) and DNSSEC NSEC3 parameters (https://www.iana.org/assignments/dnssec-nsec3-parameters). The rules for the DNSSEC algorithm registry were set in the core RFCs and updated by [RFC6014] and [RFC9157].¶
This document does not create any new IANA considerations.¶
All of the security considerations from all of the RFCs referenced in this document apply here.¶