RDAP Extension for DNS Time-To-Live (TTL Values)

Introduction While allows RDAP server operators to provide information about the content of the NS, DS, A and AAAA record(s) which are published in the DNS for a given registry object (domain or host object), it does not provide a mechanism to allow the Time-To-Live (TTL) values of those records to be included in responses. This document describes how TTL information can be included in domain and nameserver objects in RDAP responses. This document is complementary to the EPP TTL extension (), but registry operators do not need to implement that extension in their EPP server in order to implement this RDAP extension.

Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

RDAP Response Specification Servers which support this extension MUST include a ttl property in any domain and nameserver objects included in RDAP responses. The ttl property is an array of objects. These objects have the following properties:

A types property, which is an array of DNS record type mnemonics;
A value property, which is an unsigned integer indicated the TTL value for those DNS record types;
An OPTIONAL remarks property, which is an array of remarks (see ); and
An OPTIONAL events property, which is an array of events (see ).

DNS record type mnemonics MUST be in all capitals. Each DNS record type MUST only appear once in a response. TTL values MUST be unsigned integers in the range 0-2,147,483,647. Example domain object: Example nameserver object:

RDAP Conformance Servers returning responses containing TTL values MUST include the string "ttl" in the rdapConformance array.

IANA Considerations IANA is requested to register the following value in the RDAP Extensions Registry: Extension identifier: ttl Registry operator: Any Published specification: this document Contact: IETF <iesg@ietf.org> Intended usage: this extension describes how DNS TTL values can be included in RDAP responses.

Change Log

Changes from 00 to 01

Extension property name renamed to ttl.
The extension data structure is now an array allowing common TTL values, remarks and events to be mapped to multiple DNS record types.
The extension data structure may now include remarks and events.
Added normative text regarding the value of DNS record mnemonics and TTL values.