Registration Protocols Extensions (regext) G. Brown Internet-Draft ICANN Intended status: Standards Track 14 October 2024 Expires: 17 April 2025 Extensible Provisioning Protocol (EPP) mapping for DNS Time-To-Live (TTL) values draft-ietf-regext-epp-ttl-17 Abstract This document describes an extension to the Extensible Provisioning Protocol (EPP) that allows EPP clients to manage the Time-To-Live (TTL) value for domain name delegation records. About this draft This note is to be removed before publishing as an RFC. The source for this draft, and an issue tracker, may can be found at https://github.com/gbxyz/epp-ttl-extension. 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/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 17 April 2025. Copyright Notice Copyright (c) 2024 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. Brown Expires 17 April 2025 [Page 1] Internet-Draft TTL mapping for EPP October 2024 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . 4 1.2. Extension elements . . . . . . . . . . . . . . . . . . . 4 1.2.1. The element . . . . . . . . . . . . . . . . 5 1.2.1.1. Element content . . . . . . . . . . . . . . . . . 5 1.2.1.2. Supported DNS record types . . . . . . . . . . . 6 1.2.1.3. The element . . . . . . . . . . . . . 7 1.2.2. Examples . . . . . . . . . . . . . . . . . . . . . . 7 1.2.2.1. Explicit TTL value ( or command) . . . . . . . . . . . . . . . . . . . . . 7 1.2.2.2. Explicit TTL value ( policy mode) . . . . . 7 1.2.2.3. Empty value indicating default TTL ( or command, default mode) . . . . . . 7 1.2.2.4. Custom record type ( or command, default mode) . . . . . . . . . . . . . . . 7 2. EPP command mapping . . . . . . . . . . . . . . . . . . . . . 7 2.1. EPP query commands . . . . . . . . . . . . . . . . . . . 7 2.1.1. EPP command . . . . . . . . . . . . . . . . . 8 2.1.1.1. Default Mode . . . . . . . . . . . . . . . . . . 8 2.1.1.2. Policy Mode . . . . . . . . . . . . . . . . . . . 11 2.2. EPP transform commands . . . . . . . . . . . . . . . . . 14 2.2.1. EPP command . . . . . . . . . . . . . . . . 14 2.2.2. EPP command . . . . . . . . . . . . . . . . 16 3. Server processing of TTL values . . . . . . . . . . . . . . . 18 3.1. Permitted record types . . . . . . . . . . . . . . . . . 18 3.2. Use of TTL values in delegation records . . . . . . . . . 18 4. Out-of-band changes to TTL values . . . . . . . . . . . . . . 18 5. Operational considerations . . . . . . . . . . . . . . . . . 18 5.1. Operational impact of TTL values . . . . . . . . . . . . 18 5.2. When TTL values should be changed . . . . . . . . . . . . 19 5.3. Changes to server policy . . . . . . . . . . . . . . . . 19 6. Security considerations . . . . . . . . . . . . . . . . . . . 19 6.1. Fast-flux DNS . . . . . . . . . . . . . . . . . . . . . . 19 6.2. Compromised user accounts . . . . . . . . . . . . . . . . 20 7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 20 7.1. XML namespace . . . . . . . . . . . . . . . . . . . . . . 20 7.2. EPP extension registry . . . . . . . . . . . . . . . . . 21 8. Formal syntax . . . . . . . . . . . . . . . . . . . . . . . . 21 9. Implementation status . . . . . . . . . . . . . . . . . . . . 24 9.1. Verisign EPP SDK . . . . . . . . . . . . . . . . . . . . 24 Brown Expires 17 April 2025 [Page 2] Internet-Draft TTL mapping for EPP October 2024 9.2. Pepper EPP Client . . . . . . . . . . . . . . . . . . . . 25 10. Change log . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.1. Changes from 16 to 17 . . . . . . . . . . . . . . . . . 25 10.2. Changes from 15 to 16 . . . . . . . . . . . . . . . . . 25 10.3. Changes from 14 to 15 . . . . . . . . . . . . . . . . . 26 10.4. Changes from 13 to 14 . . . . . . . . . . . . . . . . . 26 10.5. Changes from 12 to 13 . . . . . . . . . . . . . . . . . 26 10.6. Changes from 11 to 12 . . . . . . . . . . . . . . . . . 26 10.7. Changes from 10 to 11 . . . . . . . . . . . . . . . . . 26 10.8. Changes from 09 to 10 . . . . . . . . . . . . . . . . . 26 10.9. Changes from 08 to 09 . . . . . . . . . . . . . . . . . 26 10.10. Changes from 07 to 08 . . . . . . . . . . . . . . . . . 27 10.11. Changes from 06 to 07 . . . . . . . . . . . . . . . . . 27 10.12. Changes from 05 to 06 . . . . . . . . . . . . . . . . . 27 10.13. Changes from 04 to 05 . . . . . . . . . . . . . . . . . 27 10.14. Changes from 04 to 05 . . . . . . . . . . . . . . . . . 27 10.15. Changes from 03 to 04 . . . . . . . . . . . . . . . . . 27 10.16. Changes from 02 to 03 . . . . . . . . . . . . . . . . . 27 10.17. Changes from 01 to 02 . . . . . . . . . . . . . . . . . 28 10.18. Changes from 00 to 01 . . . . . . . . . . . . . . . . . 28 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 12.1. Normative references . . . . . . . . . . . . . . . . . . 29 12.2. Informative references . . . . . . . . . . . . . . . . . 30 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 30 1. Introduction The principal output of any domain name registry system is a DNS zone file, which contains the delegation record(s) for names registered within a zone (such as a top-level domain). These records typically include one or more NS records, but may also include DS records for domains secured with DNSSEC ([RFC9364]), and DNAME records for IDN variants ([RFC6927]). A and/or AAAA records may also be published for nameservers where required by DNS resolvers to avoid an infinite loop. Typically, the Time-To-Live value (TTL, see Section 5 of [RFC9499]) of these records is determined by the registry operator. However, in some circumstances it may be desirable to allow the sponsoring client of a domain name to change the TTL values used for that domain's delegation: for example, to reduce the amount of time required to complete a change of DNS servers, DNSSEC deployment or key rollover, or to allow for fast rollback of such changes. This document describes an EPP extension to the domain name and host object mappings (described in [RFC5731] and [RFC5732], respectively) which allows the sponsor of a domain name or host object to change Brown Expires 17 April 2025 [Page 3] Internet-Draft TTL mapping for EPP October 2024 the TTL values of the resource record(s) associated with that object. It also describes how EPP servers should handle TTLs specified by EPP clients and how both parties co-ordinate to manage TTL values in response to changes in operational or security requirements. 1.1. 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 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. In examples, "C:" represents lines sent by a protocol client and "S:" represents lines returned by a protocol server. Indentation and white space in examples are provided only to illustrate element relationships and are not required features of this protocol. A protocol client that is authorized to manage an existing object is described as a "sponsoring" client throughout this document. XML is case sensitive. Unless stated otherwise, XML specifications and examples provided in this document MUST be interpreted in the character case presented in order to develop a conforming implementation. EPP uses XML namespaces to provide an extensible object management framework and to identify schemas required for XML instance parsing and validation. These namespaces and schema definitions are used to identify both the base protocol schema and the schemas for managed objects. The XML namespace prefixes used in examples (such as the string ttl in ttl:create) are solely for illustrative purposes. A conforming implementation MUST NOT require the use of these or any other specific namespace prefixes. In accordance with Section 3.2.2.1 of XML Schema Part 2: Datatypes [XSD-DATATYPES], the allowable lexical representations for the xs:boolean datatype are the strings "0" and "false" for the concept 'false' and the strings "1" and "true" for the concept 'true'. Implementations MUST support both styles of lexical representation. 1.2. Extension elements This extension adds additional elements to the EPP domain and host mappings. Brown Expires 17 April 2025 [Page 4] Internet-Draft TTL mapping for EPP October 2024 1.2.1. The element The element is used to define TTL values for the DNS resource records associated with domain and host objects. elements may have the following attributes, depending on whether it appears in a command or response frame: 1. "for", which is REQUIRED in both commands and responses, and which specifies the DNS record type to which the TTL value pertains. This attribute MUST have one of the following values: "NS", "DS", "DNAME", "A", "AAAA" or "custom"; 2. If the value of the "for" attribute is "custom", then the element MUST also have a "custom" attribute containing a DNS record type conforming with the regular expression in Section 3.1 of [RFC6895]. Additionally, the record type MUST be registered with IANA. 3. "min", which MUST NOT be present in command frames but MAY be present in response frames (see Section 2.1.1), and which is used by the server to indicate the lowest value that may be set; 4. "default", which MUST NOT be present in command frames but MAY be present in response frames (see Section 2.1.1), and which is used by the server to indicate the default value; 5. "max", which MUST NOT be present in command frames but MAY be present in response frames (see Section 2.1.1), and which is used by the server to indicate the highest value that may be set; When present, the value of the "min" attribute MUST be lower than the value of the "max" attribute. The "default" attribute MUST be between the "min" and "max" values, inclusively. 1.2.1.1. Element content The XML schema found in Section 8 of this document restricts the content of elements to be either: 1. a non-negative integer, indicating the value of the TTL in seconds, or 2. empty, in which case the server's default TTL for the given record type is to be applied. Brown Expires 17 April 2025 [Page 5] Internet-Draft TTL mapping for EPP October 2024 1.2.1.2. Supported DNS record types To facilitate forward compatibility with future changes to the DNS protocol, this document does not enumerate or restrict the DNS record types that can be included in the "custom" attribute of the element. The regular expression which is used to validate the values of the "custom" attribute is based on the expression found in Section 3.1 of [RFC6895], and is intended to match both existing and future RRTYPE mnemonics. This eliminates the need to update this document in the event that new DNS records that exist above a zone cut (Section 7 of [RFC9499]) are specified. Nevertheless, EPP servers which implement this extension MUST restrict the DNS record types that are accepted in and commands, and included in responses, allowing only those types that are actually published in the DNS for domain and host objects. A server that receives a or command that attempts to set TTL values for inapplicable DNS record types MUST respond with a 2306 "Parameter value policy" error. As an illustrative example, a server MAY allow clients to specify TTL values for the following record types for domain objects: 1. NS; 2. DS (if the server also implements [RFC5910]); 3. DNAME (if the server implements IDN variants using DNAME records). 1.2.1.2.1. Glue records Glue records are described in Section 7 of [RFC9499]. Servers which implement host objects ([RFC5732]) MAY allow clients to specify TTL values for A and AAAA records for host objects. A server supporting host objects which receives a command that attempts to set TTL values for A and AAAA records on a domain object MUST respond with a 2306 "Parameter value policy" error. EPP servers which use the "host attribute" model (described in Section 1.1 of [RFC5731]) MAY allow clients to specify TTL values for A and AAAA records for domain objects. Brown Expires 17 April 2025 [Page 6] Internet-Draft TTL mapping for EPP October 2024 1.2.1.3. The element The element is used by clients to request that the server include additional information in responses for domain and host objects. It has a single OPTIONAL policy attribute, which takes a boolean value with a default value of false. The semantics of this element are described in Section 2.1.1. 1.2.1.3.1. Example 1.2.2. Examples 1.2.2.1. Explicit TTL value ( or command) 3600 1.2.2.2. Explicit TTL value ( policy mode) 3600 1.2.2.3. Empty value indicating default TTL ( or command, default mode) 1.2.2.4. Custom record type ( or command, default mode) 3600 2. EPP command mapping 2.1. EPP query commands Brown Expires 17 April 2025 [Page 7] Internet-Draft TTL mapping for EPP October 2024 2.1.1. EPP command This extension defines an additional element for EPP commands and responses for domain and host objects. The EPP command is extended to support two different modes: 1. The Default Mode (Section 2.1.1.1), which requests the inclusion of all non-default TTL values in the response; and 2. The Policy Mode (Section 2.1.1.2), which requests the inclusion of TTL information for all supported DNS record types in the response, along with the minimum, default and maximum values for those records. 2.1.1.1. Default Mode If a server receives an command for a domain or host object which includes a element with a "policy" attribute that is "0" or "false", then the EPP response MUST contain records for all DNS record types that have non-default TTL values. These elements MUST NOT have the "min", "default" and "max" attributes. Example domain command with a element with a policy attribute that is false: C: C: C: C: C: C: example.com C: C: C: C: C: C: C: Example domain response to a command with a element with a policy attribute that is false: Brown Expires 17 April 2025 [Page 8] Internet-Draft TTL mapping for EPP October 2024 S: S: S: S: S: Command completed successfully S: S: S: S: example.com S: EXAMPLE1-REP S: S: S: ns1.example.com S: ns1.example.net S: S: ClientX S: ClientX S: 2023-11-08T10:14:55.0Z S: 2024-11-08T10:14:55.0Z S: S: S: S: S: 172800 S: 300 S: S: S: S: 12345 S: 13 S: 2 S: 49FD46E6C4B45C55D4AC S: S: S: S: S: ABC-12345 S: 54322-XYZ S: S: S: Example host command with a element with a policy attribute that is false: Brown Expires 17 April 2025 [Page 9] Internet-Draft TTL mapping for EPP October 2024 C: C: C: C: C: C: ns1.example.com C: C: C: C: C: C: C: Example host response to a command with a element with a policy attribute that is false: Brown Expires 17 April 2025 [Page 10] Internet-Draft TTL mapping for EPP October 2024 S: S: S: S: S: Command completed successfully S: S: S: S: ns1.example.com S: NS1_EXAMPLE1-REP S: S: 192.0.2.2 S: 2001:DB8::8:800:200C:417A S: ClientX S: ClientX S: 2023-11-08T10:14:55.0Z S: S: S: S: S: 172800 S: 86400 S: S: S: S: ABC-12345 S: 54322-XYZ S: S: S: 2.1.1.2. Policy Mode If a server receives an command for a domain or host object which includes a element with a "policy" attribute is "1" or "true", then the EPP response MUST contain records for all supported DNS record types, irrespective of whether those record types are actually in use by the object in question. These elements MUST have the "min", "default" and "max" attributes. Example domain command requesting the server policies: Brown Expires 17 April 2025 [Page 11] Internet-Draft TTL mapping for EPP October 2024 C: C: C: C: C: C: example.com C: C: C: C: C: C: C: Example domain response providing the server policies: Command completed successfully example.com EXAMPLE1-REP ns1.example.com ns1.example.net ClientX ClientX 2023-11-08T10:14:55.0Z 2024-11-08T10:14:55.0Z 172800 Brown Expires 17 April 2025 [Page 12] Internet-Draft TTL mapping for EPP October 2024 300 12345 13 2 49FD46E6C4B45C55D4AC ABC-12345 54322-XYZ Example host command requesting the server policies: C: C: C: C: C: C: ns1.example.com C: C: C: C: C: C: C: Example host response providing the server policies: Brown Expires 17 April 2025 [Page 13] Internet-Draft TTL mapping for EPP October 2024 S: S: S: S: S: Command completed successfully S: S: S: S: ns1.example.com S: NS1_EXAMPLE1-REP S: S: 192.0.2.2 S: 2001:DB8::8:800:200C:417A S: ClientX S: ClientX S: 2023-11-08T10:14:55.0Z S: S: S: S: S: 172800 S: 86400 S: S: S: S: ABC-12345 S: 54322-XYZ S: S: S: 2.2. EPP transform commands 2.2.1. EPP command This extension defines an additional element for EPP commands for domain and host objects. Brown Expires 17 April 2025 [Page 14] Internet-Draft TTL mapping for EPP October 2024 The element of the command frame MAY contain an element which MAY contain a element. This element MUST contain one or more records as described in Section 1.2. Example domain command: C: C: C: C: C: C: example.com C: 1 C: C: ns1.example.com C: ns1.example.net C: C: C: C: C: C: C: C: C: 172800 C: 300 C: C: C: C: 12345 C: 13 C: 2 C: 49FD46E6C4B45C55D4AC C: C: C: C: ABC-12345 C: C: Example host command: Brown Expires 17 April 2025 [Page 15] Internet-Draft TTL mapping for EPP October 2024 C: C: C: C: C: C: ns1.example.com C: 192.0.2.2 C: 2001:DB8::8:800:200C:417A C: C: C: C: C: C: 86400 C: C: C: ABC-12345 C: C: If an EPP server receives a command containing a TTL value that is outside the server's permitted range, it MUST reject the command with a 2004 "Parameter value range error" response. 2.2.2. EPP command This extension defines an additional element for EPP commands for domain and host objects. The element of the command frame MAY contain an element which MAY contain a element. This element MUST contain one or more records as described in Section 1.2. Example domain command: Brown Expires 17 April 2025 [Page 16] Internet-Draft TTL mapping for EPP October 2024 C: C: C: C: C: C: example.com C: C: C: C: C: C: C: 86400 C: C: C: ABC-12345 C: C: Example host command: C: C: C: C: C: C: ns1.example.com C: C: C: C: C: 86400 C: 3600 C: C: C: ABC-12345 C: C: If an EPP server receives an command containing a TTL value that is outside the server's permitted range, it MUST reject the command with a 2004 "Parameter value range error" response. Brown Expires 17 April 2025 [Page 17] Internet-Draft TTL mapping for EPP October 2024 3. Server processing of TTL values 3.1. Permitted record types Servers SHOULD restrict the supported DNS record types in accordance with their own policy. For example, a server MAY allow clients to specify TTL values for DS records only. A server which receives a or command which includes a restricted record type MUST respond with a 2306 "Parameter value policy" error. Clients can discover the DNS record types for which an EPP server permits TTL values to be changed by performing a "Policy Mode" command, as outlined in Section 2.1.1.2. 3.2. Use of TTL values in delegation records EPP servers which implement this extension SHOULD use the values provided by EPP clients for the TTL values of records published in the DNS for domain and (if supported) host objects. EPP servers that use the "host attribute" model SHOULD use any NS, A and/or AAAA TTL values specified for the domain object when publishing NS, A and/or AAAA records derived from host attributes. 4. Out-of-band changes to TTL values EPP server operators MAY, in order to address operational or security issues, make changes to TTL values out-of-band (that is, not in response to an command received from the sponsoring client). Server operators MAY also implement automatic reset of TTL values, so that they revert to the default value a certain amount of time after an update has been made. If a TTL value is changed out-of-band, EPP server operators MAY notify the sponsoring client using the EPP Change Poll extension ([RFC8590]), which provides a generalised method for EPP servers to notify clients of changes to objects under their sponsorship. 5. Operational considerations 5.1. Operational impact of TTL values Registry operators must consider the balance between registrants' desire for changes to domains to be visible in the DNS quickly, and the increased DNS query traffic that short TTLs can bring. Brown Expires 17 April 2025 [Page 18] Internet-Draft TTL mapping for EPP October 2024 Registry operators SHOULD implement limits on the maximum and minimum accepted TTL values that are narrower than the values permitted in the XML schema in the Formal syntax (which were chosen to allow any TTL permitted in DNS records), in order to prevent scenarios where an excessively high or low TTL causes operational issues on either side of the zone cut. Section 4 describes how server operators MAY unilaterally change TTL values in order to address operational or security issues, or only permit changes for limited time periods (after which TTLs revert to the default). 5.2. When TTL values should be changed A common operational mistake is changing of DNS record TTLs during or after the planned change to the records themselves. This arises due to a misunderstanding about how TTLs work. It is RECOMMENDED that guidance be provided to users so they are aware that changes to a TTL are only effective in shortening transition periods if implemented a period of time — at least equal to the current TTL — _before_ the planned change. The latency between receipt of the command and the actual publication of the changes in the DNS should also be taken into consideration in this calculation. 5.3. Changes to server policy Registry operators may change their policies relating to TTL values from time to time. Previously configured TTL values may consequently fall outside a newly-applied policy. This document places no obligation on EPP server operators in respect of these values, and server operators may, as part of a policy change, change the TTL values specified by clients for domain and host objects. Section 4 describes how such out-of-band changes should be carried out. 6. Security considerations 6.1. Fast-flux DNS Some malicious actors use a technique called "fast flux DNS" ([SAC-025]) to rapidly change the DNS configuration for a zone in order to evade takedown and law enforcement activity. Server operators should take this into consideration when setting the lower limit on TTL values, since a short TTL on delegations may enhance the effectiveness of fast flux techniques on evasion. Brown Expires 17 April 2025 [Page 19] Internet-Draft TTL mapping for EPP October 2024 Client implementations which provide an interface for customers to configure TTL values for domain names should consider implementing controls to deter and mitigate abusive behaviour, such as those outlined in the "Current and Possible Mitigation Alternatives" section of [SAC-025]. 6.2. Compromised user accounts An attacker who obtains access to a customer account at a domain registrar which supports this extension could make unauthorised changes to the NS and/or glue records for a domain, and then increase the associated TTLs so that the changes persist in caches for a long time after the attack has been detected. Client implementations which provide an interface for customers to configure TTL values for domain names should consider implementing upper limits in order to reduce the impact of account compromise, in addition to best practices relating to credential management, multi- factor authentication, risk-based access control, and so on. 7. IANA considerations 7.1. XML namespace This document uses URNs to describe XML namespaces and XML schemas conforming to a registry mechanism described in [RFC3688]. The following URI assignment is requested of IANA: Registration for the TTL namespace: *URI:* urn:ietf:params:xml:ns:epp:ttl-1.0 *Registrant Contact:* IESG *XML:* None. Namespace URIs do not represent an XML specification Registration for the TTL XML schema: *URI:* urn:ietf:params:xml:schema:epp:ttl-1.0 *Registrant Contact:* IESG *XML:* See the "Formal syntax" section of this document Brown Expires 17 April 2025 [Page 20] Internet-Draft TTL mapping for EPP October 2024 7.2. EPP extension registry The EPP extension described in this document is to be registered by IANA in the Extensions for the "Extensible Provisioning Protocol (EPP)" registry described in [RFC7451]. The details of the registration are as follows: *Name of Extension:* Extensible Provisioning Protocol (EPP) Mapping for DNS Time-To-Live (TTL) values *Document Status:* Standards Track *Reference:* URL of this document *Registrant Name and Email Address:* IESG *TLDs:* Any *IPR Disclosure:* None *Status:* Active *Notes:* None 8. Formal syntax The formal syntax presented here is a complete schema representation of the extension suitable for automated validation of EPP XML instances. Extensible Provisioning Protocol v1.0 extension schema for Time-To-Live (TTL) values for domain and host objects. Brown Expires 17 April 2025 [Page 21] Internet-Draft TTL mapping for EPP October 2024 Brown Expires 17 April 2025 [Page 22] Internet-Draft TTL mapping for EPP October 2024 9. Implementation status This section is to be removed before publishing as an RFC. 9.1. Verisign EPP SDK *Organization:* Verisign Inc. *Name:* Verisign EPP SDK Brown Expires 17 April 2025 [Page 24] Internet-Draft TTL mapping for EPP October 2024 *Description:* The Verisign EPP SDK includes both a full client implementation and a full server stub implementation of this specification. *Level of maturity:* Development *Coverage:* All aspects of the protocol are implemented. *Licensing:* GNU Lesser General Public License *Contact:* jgould@verisign.com *URL:* https://www.verisign.com/en_US/channel-resources/domain- registry-products/epp-sdks 9.2. Pepper EPP Client *Name:* Pepper EPP Client *Description:* The Pepper EPP client fully implements this specification. The underlying Net::EPP:: Perl module also implements this specification. *Level of maturity:* Development *Coverage:* All aspects of the protocol will be implemented. *Licensing:* Perl Artistic License *Contact:* The author of this document. *URL:* https://github.com/gbxyz/pepper 10. Change log This section is to be removed before publishing as an RFC. 10.1. Changes from 16 to 17 1. Further updates as suggested during IESG review. 10.2. Changes from 15 to 16 1. Updates as suggested during IESG review. Brown Expires 17 April 2025 [Page 25] Internet-Draft TTL mapping for EPP October 2024 10.3. Changes from 14 to 15 1. Updates as suggested during AD review. 2. In the last paragraph of Section 3.2, make both lists of RR types be the same. 3. Update error codes to be consistent: 2004 (range error) when the TTL value is outside the permitted range, and 2306 (policy error) for an invalid record type. 4. Correct section in reference to RFC 6895 (thanks Jasdip Singh). 5. Minor typographic fixes (thanks Jasdip Singh). 10.4. Changes from 13 to 14 1. Resolve remaining nit before IESG submission. 10.5. Changes from 12 to 13 1. Updates as per the document shepherd's suggestions. 10.6. Changes from 11 to 12 1. Updates as per the document shepherd's email to the list of 2024-06-10. 10.7. Changes from 10 to 11 1. Fix double word in Section 3.2. 10.8. Changes from 09 to 10 Changes resulting from the Dnsdir review: 1. Fixed example IPv6 addresses to use the preferred prefix 2001:DB8::. 2. Added paragraph to Section 3.1 describing how clients can use the Policy Mode command (Section 2.1.1.2) to discover the DNS record types supported by the server. 10.9. Changes from 08 to 09 1. Some wording changes suggested by James Gould and Tim Wicinski. Brown Expires 17 April 2025 [Page 26] Internet-Draft TTL mapping for EPP October 2024 10.10. Changes from 07 to 08 1. Some wording changes suggested by Rick Wilhelm. 10.11. Changes from 06 to 07 1. Minor wording changes and nits reported by JG. 10.12. Changes from 05 to 06 1. Changed how commands work so that a element is required in order for elements to be included in the response. Thanks to JG for this feedback. 10.13. Changes from 04 to 05 1. removed the erroneous required="true" attribute from the min, default and max attributes of the responseTTLType type (thanks JG). 2. fixed the reference to RFC 6895 (thanks HS). 10.14. Changes from 04 to 05 1. Add the Verisign EPP SDK to Section 9. 2. Add the element and document how it affects server responses. 3. Updated examples to exercise more of the schema. 4. Minor schema issue fixed. 10.15. Changes from 03 to 04 1. Changed the for attribute to be an enumeration and added the custom attribute. 2. Added the min, default and max attributes. 3. Apply feedback from Jim Gould. 10.16. Changes from 02 to 03 1. Rolled back the "straw man" syntax from 02. ttl:ttl now has a for attribute which can be any DNS record type. Section 1.2.1.2 describes how the set of supported record types may be limited. Brown Expires 17 April 2025 [Page 27] Internet-Draft TTL mapping for EPP October 2024 2. Removed the global/explicit models and just use the explicit model. 3. Removed the cascading effect where a TTL set on a domain affects subordinate hosts. 10.17. Changes from 01 to 02 1. Renamed the ttl:seconds XSD type to ttl:container, and the ttl:nonNegativeInteger type to ttl:ttlType, to permit multiple TTL values. 2. Converted XML instances from artwork to source code. 10.18. Changes from 00 to 01 1. Incorporate feedback from Jim Gould. 2. Add wording to describe how TTL values are jointly managed by both clients and servers. 3. Fix minimum/maximum TTL value and schema namespace (thanks Patrick Mevzek). 4. Moved text on how the server should handle impermissible TTL values from the top of Section 4 to Sections 3.2.1 and 3.2.2 (thanks Rick Wilhelm). 5. Namespace changed from urn:ietf:params:xml:ns:ttl-1.0 to urn:ietf:params:xml:ns:epp:ttl-1.0. 6. Added discussion on EPP servers which use the host attribute model in Section 3.2 (thanks Hugo Salgado). 7. Added a Change Log (Section 10). 11. Acknowledgements The author wishes to thank the following people for their advice and feedback during the development of this document: 1. James Gould 2. Hugo Salgado 3. Patrick Mevzek 4. Rick Wilhelm Brown Expires 17 April 2025 [Page 28] Internet-Draft TTL mapping for EPP October 2024 5. Marc Groeneweg 6. Ties de Kock 7. Tim Wicinski 8. Jasdip Singh 12. References 12.1. Normative references [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC5731] Hollenbeck, S., "Extensible Provisioning Protocol (EPP) Domain Name Mapping", STD 69, RFC 5731, DOI 10.17487/RFC5731, August 2009, . [RFC5732] Hollenbeck, S., "Extensible Provisioning Protocol (EPP) Host Mapping", STD 69, RFC 5732, DOI 10.17487/RFC5732, August 2009, . [RFC5910] Gould, J. and S. Hollenbeck, "Domain Name System (DNS) Security Extensions Mapping for the Extensible Provisioning Protocol (EPP)", RFC 5910, DOI 10.17487/RFC5910, May 2010, . [RFC6895] Eastlake 3rd, D., "Domain Name System (DNS) IANA Considerations", BCP 42, RFC 6895, DOI 10.17487/RFC6895, April 2013, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [XSD-DATATYPES] World Wide Web Consortium (W3C), "XML Schema Part 2: Datatypes Second Edition", October 2004, . Brown Expires 17 April 2025 [Page 29] Internet-Draft TTL mapping for EPP October 2024 12.2. Informative references [RFC6927] Levine, J. and P. Hoffman, "Variants in Second-Level Names Registered in Top-Level Domains", RFC 6927, DOI 10.17487/RFC6927, May 2013, . [RFC7451] Hollenbeck, S., "Extension Registry for the Extensible Provisioning Protocol", RFC 7451, DOI 10.17487/RFC7451, February 2015, . [RFC8590] Gould, J. and K. Feher, "Change Poll Extension for the Extensible Provisioning Protocol (EPP)", RFC 8590, DOI 10.17487/RFC8590, May 2019, . [RFC9364] Hoffman, P., "DNS Security Extensions (DNSSEC)", BCP 237, RFC 9364, DOI 10.17487/RFC9364, February 2023, . [RFC9499] Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219, RFC 9499, DOI 10.17487/RFC9499, March 2024, . [SAC-025] ICANN Security and Stability Advisory Committee (SSAC), "SSAC Advisory on Fast Flux Hosting and DNS", SAC 25, January 2008, . Author's Address Gavin Brown ICANN 12025 Waterfront Drive, Suite 300 Los Angeles, CA 90292 United States of America Email: gavin.brown@icann.org URI: https://www.icann.org/ Brown Expires 17 April 2025 [Page 30]