Network Working Group P. Kowalik Internet-Draft DENIC eG Intended status: Standards Track A. Blinn Expires: 7 December 2026 J. Kolker GoDaddy Inc. S. Kerola Cloudflare, Inc. 5 June 2026 Domain Connect Protocol - DNS provisioning between Services and DNS Providers draft-ietf-dconn-domainconnect-02 Abstract This document provides specification of the Domain Connect Protocol that was built to support DNS configuration provisioning between Service Providers (hosting, social, email, hardware, etc.) and DNS Providers. 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 7 December 2026. Copyright Notice Copyright (c) 2026 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 Kowalik, et al. Expires 7 December 2026 [Page 1] Internet-Draft Domain Connect June 2026 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 2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Primary Use Cases . . . . . . . . . . . . . . . . . . . . 4 2.2. Use Cases out of scope . . . . . . . . . . . . . . . . . 5 4. Protocol design . . . . . . . . . . . . . . . . . . . . . . . 10 4.1. Templates . . . . . . . . . . . . . . . . . . . . . . . . 10 4.2. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 11 5. Protocol Flows Overview . . . . . . . . . . . . . . . . . . . 11 5.1. General information . . . . . . . . . . . . . . . . . . . 11 5.2. The Synchronous Flow . . . . . . . . . . . . . . . . . . 12 6. Domain Connect Objects and Templates . . . . . . . . . . . . 15 6.1. Template Definition . . . . . . . . . . . . . . . . . . . 15 6.2. Template Record . . . . . . . . . . . . . . . . . . . . . 20 6.3. Template Considerations . . . . . . . . . . . . . . . . . 28 6.3.1. Template Scope . . . . . . . . . . . . . . . . . . . 29 6.3.2. Sub Domains . . . . . . . . . . . . . . . . . . . . . 29 6.3.3. Variable Scope Minimisation . . . . . . . . . . . . . 29 6.4. Public Key Publication . . . . . . . . . . . . . . . . . 30 7. DNS Provider Discovery . . . . . . . . . . . . . . . . . . . 32 8. Applying Domain Connect . . . . . . . . . . . . . . . . . . . 38 8.1. Endpoints . . . . . . . . . . . . . . . . . . . . . . . . 38 8.2. Query Supported Template . . . . . . . . . . . . . . . . 38 8.3. Synchronous Flow . . . . . . . . . . . . . . . . . . . . 40 8.3.1. Apply Template URL . . . . . . . . . . . . . . . . . 40 8.3.2. Parameters/properties . . . . . . . . . . . . . . . . 40 8.3.3. Template Apply Request . . . . . . . . . . . . . . . 44 8.3.4. Signature Verification . . . . . . . . . . . . . . . 45 8.3.5. Template Apply Response . . . . . . . . . . . . . . . 45 8.3.6. Template Apply Error Response . . . . . . . . . . . . 46 8.4. Verification of Changes . . . . . . . . . . . . . . . . . 47 9. Resolving Template Variables . . . . . . . . . . . . . . . . 47 9.1. Variables . . . . . . . . . . . . . . . . . . . . . . . . 47 9.1.1. Variable Syntax . . . . . . . . . . . . . . . . . . . 48 9.1.2. Special and Built-In Variables . . . . . . . . . . . 48 9.2. Variable substitution . . . . . . . . . . . . . . . . . . 48 9.2.1. Input Values . . . . . . . . . . . . . . . . . . . . 48 9.2.2. Processing . . . . . . . . . . . . . . . . . . . . . 49 9.3. Host Name Rendering . . . . . . . . . . . . . . . . . . . 49 9.3.1. Input Values . . . . . . . . . . . . . . . . . . . . 49 9.3.2. Processing . . . . . . . . . . . . . . . . . . . . . 50 9.3.3. Examples of host processing . . . . . . . . . . . . . 50 Kowalik, et al. Expires 7 December 2026 [Page 2] Internet-Draft Domain Connect June 2026 9.4. SPF Record Merging . . . . . . . . . . . . . . . . . . . 51 10. Template Application . . . . . . . . . . . . . . . . . . . . 52 10.1. Template State in DNS Providers system . . . . . . . . . 52 10.2. Steps to Apply a Template . . . . . . . . . . . . . . . 53 10.3. Group Filtering . . . . . . . . . . . . . . . . . . . . 54 10.3.1. Group Filtering and Template State . . . . . . . . . 55 10.4. Conflict Detection . . . . . . . . . . . . . . . . . . . 55 10.4.1. Conflict Detection Special Handling . . . . . . . . 56 10.5. Calculating Conflict Resolution . . . . . . . . . . . . 57 10.6. User Authorization of Changes . . . . . . . . . . . . . 57 10.7. Template Application . . . . . . . . . . . . . . . . . . 58 10.8. Examples . . . . . . . . . . . . . . . . . . . . . . . . 58 11. Security Considerations . . . . . . . . . . . . . . . . . . . 59 11.1. Template Variable Phishing . . . . . . . . . . . . . . . 59 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59 12.1. Underscore "_domainconnect" DNS Node Name . . . . . . . 59 12.2. Domain Connect Settings Properties Registry . . . . . . 59 Implementation Status . . . . . . . . . . . . . . . . . . . . . . 61 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 62 Change History . . . . . . . . . . . . . . . . . . . . . . . . . 62 Normative References . . . . . . . . . . . . . . . . . . . . . . 65 Informative References . . . . . . . . . . . . . . . . . . . . . 67 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 67 A.1. Example Template . . . . . . . . . . . . . . . . . . . . 67 A.2. Example Records: Single static host record . . . . . . . 68 A.3. Example Records: Single variable host record for A . . . 69 A.4. Example Records: Unspecified record type CAA . . . . . . 69 A.5. Example: Template application to DNS Zone and Conflict Resolution . . . . . . . . . . . . . . . . . . . . . . . 70 A.6. Example: SPF Record Merging . . . . . . . . . . . . . . . 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 73 1. Introduction Connecting a domain name to a service should be a simple and straightforward process. However, historically, users have faced a complex and often frustrating task involving manual DNS configuration. Traditional methods are unreliable, require deep technical knowledge of DNS, and result in outdated and confusing instructions from Service Providers. This leads to user frustration, support overhead, and abandoned setups. Kowalik, et al. Expires 7 December 2026 [Page 3] Internet-Draft Domain Connect June 2026 To address these challenges, Domain Connect offers a streamlined and automated solution. It empowers Service Providers to easily enable their services to work with user domains, simplifying both DNS provider discovery and DNS configuration. By abstracting away the complexities of manual DNS management through user-friendly web interactions, standard authentication, and template-based configurations, Domain Connect significantly improves the user experience. 2. Use Cases 2.1. Primary Use Cases The following use cases illustrate the wide range of applications where Domain Connect simplifies and automates DNS configuration, from basic service onboarding to complex, dynamic DNS management scenarios. * *SaaS Provider with One-Off DNS Configuration:* A Software as a Service (SaaS) Provider offering functionality with an option to assign own domain name, such as web hosting or email, can utilize Domain Connect to streamline the process of configuring DNS records for their customers. This automation eliminates the need for manual configuration and simplifies the onboarding experience for users. * *SaaS Provider with Multi-Step DNS Configuration:* Some SaaS Providers may require a multi-step DNS configuration process. For example, a service might require initial verification of domain ownership through a TXT record, followed by the creation of CNAME records for different subdomains. Domain Connect can handle such scenarios by utilizing record groups ("groupId") to apply parts of a template in separate interactions, each with explicit user consent. * *On-Premise Service with Publicly Accessible DNS Service:* An on- premise service, such as a local network device or server, can also benefit from Domain Connect if it utilizes a publicly accessible DNS service. By leveraging Domain Connect, the service can automatically update DNS records as needed, ensuring that the service remains accessible through its domain name. * *Tool or Service with Regularly Updated DNS Entries:* A tool or service that requires regular updates to DNS entries, such as a dynamic DNS service or a DNS-based load balancer, can use Domain Connect to automate the process. Kowalik, et al. Expires 7 December 2026 [Page 4] Internet-Draft Domain Connect June 2026 * *Packaged Software Provider:* A packaged software provider, whether open-source or proprietary, can integrate Domain Connect into their installation and configuration process. This allows the software to automatically configure necessary DNS records during installation, simplifying the setup process for users. However, if the software is installed on a private network with a private DNS service, it might not be directly compatible with Domain Connect, unless the DNS service provides Domain Connect endpoints accessible to the installation process. 2.2. Use Cases out of scope While Domain Connect offers significant advantages in automating DNS configuration, it's important to recognize scenarios where it might not be the ideal solution: * *Automation or CI/CD Pipelines:* Domain Connect is primarily designed for user-driven DNS configuration, where an end user grants consent and applies changes. Automating this process within CI/CD pipelines or other automated workflows is outside the scope of this specification. * *Private/Enterprise DNS with Public SaaS Providers:* Domain Connect relies on public DNS records and endpoints to facilitate discovery and configuration. If a private or enterprise DNS service is used, it might not be directly compatible with Domain Connect, unless the DNS service provides publicly accessible Domain Connect endpoints. 3. Terminology 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. The Terms like "*Registrar*", "*Authoritative server*", "*Zone*", "*Zone Apex*" or "*Sub Domain*" are used as defined in [RFC8499]. This specification uses the Augmented Backus-Naur Form (ABNF) notation of [RFC5234]. The following ABNF rules are imported from the normative references [RFC5234]. ALPHA = %x41-5A / %x61-7A ; A-Z / a-z DIGIT = %x30-39 ; 0-9 Kowalik, et al. Expires 7 December 2026 [Page 5] Internet-Draft Domain Connect June 2026 The following definitions and rules are imported normatively from other documents. "a-label": "A-label" as defined in Section 2.3.2.1 of [RFC5890]. "u-label": "U-label" as defined in Section 2.3.2.1 of [RFC5890]. "ldh-label": "NR-LDH Label" as defined in Section 2.3.2.2. of [RFC5890]. "domain-name": "Internationalized Domain Name" as defined in Section 2.3.2.3. of [RFC5890]. "state": "state" as defined in Appendix A. Section A5 of [RFC6749]. "redirect_uri": "redirect_uri" as defined in Appendix A, Section A.6 of [RFC6749]. "unicode-assignable": "Unicode Assignables" as defined in Section 4.3 of [RFC9839]. "JSON number": "number" as defined in Section 6 of [RFC8259]. "srv-rdata": SRV RDATA fields as defined in Section 3.1 of [RFC2782]. "service-name": "Service Name" as defined in Section 5.1 of [RFC6335]. "presentation format": "Presentation Format" as defined in Section 1 of [RFC9499]. The following additional syntax rules are defined in this document and used normatively throughout. "dc-name-char": any Unicode Assignable code point allowed in "domain-name" except "%" and "@" The following additional ABNF rules are defined in this document and used normatively throughout. ; ---- Identifier rules ---- dc-id = 1*63( ALPHA / DIGIT / "-" / "_" / "." ) ; non-empty token, max 63 octets; ; used for providerId, serviceId, groupId, ; instanceId Kowalik, et al. Expires 7 December 2026 [Page 6] Internet-Draft Domain Connect June 2026 dc-id-list = dc-id *( "," dc-id ) ; comma-separated list of dc-id values; ; used for groupId parameter dc-host-list = domain-name *( *SP "," *SP domain-name ) ; comma-separated list of domain names ; ---- Other parameter rules ---- dc-sig = 1*( ALPHA / DIGIT / "+" / "/" / "=" ) ; standard base64 alphabet per RFC 4648 Section 4 dc-underscore-label = "_" 1*( ALPHA / DIGIT / "-" ) ; RFC 8552 underscore-prefixed DNS label, ; max 63 octets total dc-key-label = a-label / dc-underscore-label ; plain ACE label or RFC 8552 underscore label; ; used for the key parameter dc-pubkey-domain = *( dc-underscore-label "." ) domain-name ; zero or more underscore labels prepended ; to an IDNA domain name, per RFC 8552 ; user for syncPubKeyDomain dc-display-name = 1*255unicode-assignable ; non-empty string of at most 255 Unicode ; Assignable code points per RFC 9839 Section 4.3; ; used for providerName and serviceName dc-description-text = 0*2048unicode-assignable ; a string of at most 2048 Unicode ; Assignable code points per RFC 9839 Section 4.3; ; used for description and variableDescription dc-version = %x31-39 *DIGIT ; positive integer, no leading zeros, ; no fraction, no exponent; ; a strict subset of JSON number (RFC 8259 ; Section 6); used for template version ; ---- Variable expression rules ---- variable-expression = named-variable / template-apex-var ; parameterized expression in a template field named-variable = "%" variable-name "%" ; %-delimited named variable Kowalik, et al. Expires 7 December 2026 [Page 7] Internet-Draft Domain Connect June 2026 template-apex-var = "@" ; zone-apex / fqdn shorthand; MUST appear alone ; in host/name or pointsTo/data fields variable-name = 1*( ALPHA / DIGIT / "-" / "_" ) ; identifier of a template variable ; ---- Template record field rules ---- dc-record-type = ( "A" / "AAAA" / "CNAME" / "MX" / "TXT" / "SRV" / "SPFM" / "NS" ) ; named core and pseudo record types / "TYPE" 1*DIGIT ; unknown type per RFC 3597 / 1*(ALPHA / DIGIT / "-") ; any other IANA-registered RR type name dc-essential = "Always" / "OnApply" ; default is "Always" dc-txt-conflict-mode = "None" / "All" / "Prefix" ; default is "None" dc-conflict-prefix = 1*(%x21-7E) ; non-empty printable ASCII (U+0021..U+007E); ; no variable expressions permitted ; -- property value field -- dc-prop-value = *( dc-prop-char / dc-rdata-escape ) ; DNS presentation format (RFC 9499); dc-prop-char = %x20-7E ; space and all printable ASCII (U+0020..U+007E); dc-rdata-escape = "\" ( 3DIGIT / %x21-7E ) ; RFC 1035 Section 5.1 octet escape: ; "\DDD" three decimal digits, or ; "\" followed by any printable non-digit character ; -- host / name / pointsTo / target fields -- dc-host-tmpl = template-apex-var ; "@" alone / 1*( named-variable / dc-name-char ) ; mix of literal chars and %-variables Kowalik, et al. Expires 7 December 2026 [Page 8] Internet-Draft Domain Connect June 2026 dc-pointsto-tmpl = template-apex-var ; "@" alone / 1*( dc-name-char / named-variable ) ; mix of literal chars and %-variables dc-pointsto-nat-tmpl = 1*( dc-name-char / named-variable ) ; mix of literal chars and %-variables ; -- integer fields with optional variable -- dc-ttl-tmpl = 1*DIGIT / named-variable ; constant seconds, or a sole %-variable dc-ttl-value = 1*DIGIT ; non-negative integer seconds, resolved dc-uint16-tmpl = ( %x30-39 *4DIGIT ) / named-variable ; 0-65535 literal, or a sole %-variable dc-uint16-value = %x30-39 *4DIGIT ; resolved non-negative integer, max 5 digits, ; semantic range 0-65535 ; -- SRV-specific string fields -- dc-srv-protocol = "_tcp" / "_udp" / "_sctp" / "_dccp" ; underscore-prefixed transport per RFC 2782 dc-srv-service = dc-underscore-label ; underscore-prefixed service name per RFC 6335 Internationalized domain names (IDN) are handled in accordance with [RFC5891]. Where a parameter description specifies "domain-name", both the ACE ("A-label") and the Unicode ("U-label") forms are accepted. Service Provider: An entity that offers products and services that are configured or accessed using domain names. These services typically rely on DNS for setup, discovery and/or operation. Examples include web hosting, email services, cloud platforms, and other online applications. DNS Provider: An entity that offers DNS zone hosting services. DNS Providers are responsible for hosting the DNS zone for a domain name and providing the necessary tools to manage the DNS records. DNS Provider would be an Authoritative server operator for the hosted zones, or would have a contractual relationship with the operator to manage zone distribution over DNS. Kowalik, et al. Expires 7 December 2026 [Page 9] Internet-Draft Domain Connect June 2026 User: Refers to the end-user who has means to control domain name's DNS configuration at DNS Provider and wishes to configure it to work with a service provided by a Service Provider. Service Template/Template: A structured data format that describes a set of configurations for DNS records required by a Service Provider to configure a certain service together with metadata related to the control flow of Domain Connect protocol. A template is used as a means of communication between Service Provider and DNS Provider. Certain labels, parameters, endpoints, and registry entries are present in this specification with _Reserved_ status. These items appear in the original Domain Connect community specification [DC-SPEC] and are reserved here to ensure back-compatibility with that specification. Reserved items MUST NOT be redefined in any manner that is incompatible with their definition in [DC-SPEC]. They MAY be used or further defined only in specifications or drafts that extend this document, provided those specifications normatively require this document as their base and are compatible with [DC-SPEC]. 4. Protocol design 4.1. Templates Templates are core to Domain Connect, as they fully describe a service owned by a Service Provider and contain all of the information necessary to enable and operate/maintain the service in the form of a set of records. The individual records in a template MAY be assigned to a group identified by a "groupId". This allows for the application of templates in different stages. For example, an email provider might first set a TXT record to verify the domain, and later set an MX record to configure email delivery. While done separately, both changes are fundamentally part of the same service. Templates MAY also contain variable portions, as often values of data in DNS change based on the implementation and/or user of the service (e.g. the IP address of a service, a user id, etc.). The template is defined by the Service Provider and manually onboarded with the DNS Provider. This is an out-of-band process between the Service Provider and the DNS Provider and not covered by this specification. Kowalik, et al. Expires 7 December 2026 [Page 10] Internet-Draft Domain Connect June 2026 4.2. Trust Model DNS Providers are trusted parties by virtue of their existing full access to the DNS zone. DNS Providers enforce user authorization checks before enacting any DNS zone changes, and present proposed changes to the user in a human-readable form. Service Providers are not assumed to be trusted by default. A malicious actor may attempt to exploit user trust by impersonating a legitimate Service Provider. Trust between DNS Providers and Service Providers is therefore established out-of-band - typically through an onboarding process involving contractual agreements or template acceptance policies - during which the DNS Provider verifies the legitimacy of the Service Provider and its templates. Templates define and restrict the permitted scope of DNS modifications. By fixing the records that a Service Provider may affect, templates ensure that no changes beyond the approved scope can be applied. 5. Protocol Flows Overview 5.1. General information To attach a domain name to a service provided by a Service Provider, the user would first enter their domain name. Instead of relying on examination of the nameservers and mapping these to DNS Providers, DNS Provider discovery is handled through simple records in DNS and an API. The Service Provider queries for a specific record in the zone that returns a REST endpoint to initiate the protocol. When this endpoint is called, a Domain Connect compliant DNS Provider returns information about that domain and how to configure it using Domain Connect. To apply the changes to DNS, this document defines a synchronous web flow. The DNS Provider presents a consent UX to the user and applies the template within the same interaction session. [DC-SPEC] also defines an asynchronous flow based on OAuth. Other flows may be defined in the future. Therefore, although it is RECOMMENDED to cover the synchronous flow, implementers MAY decide not to do so and only implement other flows not defined in this document. The signaling offered by DNS Provider discovery allows for that. Kowalik, et al. Expires 7 December 2026 [Page 11] Internet-Draft Domain Connect June 2026 5.2. The Synchronous Flow This flow is tailored for the Service Provider that requires a user- attended, one-time change to DNS configuration. In this flow, the user is present throughout: they authenticate with the DNS Provider and explicitly consent to the changes within a single interaction session. The term "synchronous" refers to this user-interaction model - not to immediate DNS propagation. The DNS Provider commits to applying the template upon user consent, but the changes MAY be queued internally and propagation to authoritative servers MAY take additional time. Service Providers MUST NOT assume that DNS records are resolvable immediately after the flow completes; see Section 8.4. ,-. `-' /|\ | ,----------------. ,------------. ,----------. / \ |Service Provider| |DNS Provider| |DNS Server| User `--------+-------' `------+-----' `-----+----' 1 Provides domain name | | |------------->| | | | | | | | | 2 Initiates DNS discovery | | |---------------------------------------->| | | | | | | 3 Responds with | | | discovery URL fragment | | |<----------------------------------------| | | | | | 4 Requests DNS Provider settings | | |----------------->| | | | | | | 5 Provides settings| | | |<-----------------| | | | | | | 6 Queries for supported template | | |----------------->| | | | | | | 7 Responds template| | | support status | | | |<-----------------| | | | | | 8 Presents connection link | | |<-------------| | | | | | | | 9 Navigates to DNS Provider | | Kowalik, et al. Expires 7 December 2026 [Page 12] Internet-Draft Domain Connect June 2026 |-------------------------------->| | | | | | | | | | _________________________________________________________| ! ALT / if the template requires signing ! !_____/ | | ! ! 10 Lookup URL | ! ! signature keys (DNS) ! ! |<-----------------| ! ! | | ! ! | |----. ! ! | | | 11 Check ! ! | |<---' request URL ! ! | | signature ! ! | | ! !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~! | | | | | 12 Requests authentication | | |<--------------------------------| | | | | | | 13 Authenticate | | |-------------------------------->| | | | | | | | |----. | | | | | 14 Check domain | | | |<---' ame in | | | | customer's | | | | account | | | | | | | | | 15 Requests consent for DNS changes | |<--------------------------------| | | | | | | 16 Confirms consent | | |-------------------------------->| | | | | | | | 17 Apply changes to DNS| | | |--------------------->| | | | | | 18 Redirect/ Close window | | |<- - - - - - - - -| | | | | | | | 19 Query DNS records | | |---------------------------------------->| | | | | | | 20 New DNS records | | |<----------------------------------------| | | | | Kowalik, et al. Expires 7 December 2026 [Page 13] Internet-Draft Domain Connect June 2026 21 Report success | | |<-------------| | | Figure 1: Sequence diagram of Synchronous Flow Steps: 1. *User Provides Domain Name*: The user initiates the process by providing their domain name to the Service Provider. 2. *Service Provider Initiates DNS Discovery*: The Service Provider queries the DNS provider to discover the Domain Connect settings for the given domain. 3. *DNS Provider Responds with Discovery URL Fragment*: The DNS Provider responds with a URL fragment containing information where to query settings of DNS provider for a domain name. 4. *Service Provider Requests DNS Provider Settings*: The Service Provider uses the URL fragment to request the complete Domain Connect settings from the DNS Provider. 5. *DNS Provider Provides Settings*: The DNS Provider provides the settings, including information about API endpoints. 6. *Service Provider Queries for Supported Template*: The Service Provider checks if the DNS Provider supports the specific template required for the service. 7. *DNS Provider Responds with Template Support Status*: The DNS Provider confirms if they support the requested template. 8. *Service Provider Presents Connection Link*: The Service Provider presents a connection link to the user, which leads to the DNS Provider's Domain Connect service. 9. *User Navigates to DNS Provider*: The user navigates the link and user agent is directed to the DNS Provider's website. 10. *DNS Provider Performs URL Lookup and Signature Key Verification (if required)*: If the template requires signing, the DNS Provider looks up the URL signature keys in DNS. 11. *DNS Provider Checks Request URL Signature (if required)*: The DNS Provider verifies the signature of the request URL. 12. *Service Provider Requests Authentication*: The Service Provider requests authentication from the user. Kowalik, et al. Expires 7 December 2026 [Page 14] Internet-Draft Domain Connect June 2026 13. *User Authenticates*: The user authenticates with the DNS Provider. 14. *DNS Provider Checks Domain Name in Customer's Account*: The DNS Provider verifies that the user is authorized to make change to the domain's DNS zone. 15. *DNS Provider Requests Consent for DNS Changes*: The DNS Provider asks the user for consent to apply the changes to the DNS zone. 16. *User Confirms Consent*: The user confirms their consent to the DNS changes. 17. *DNS Provider Applies Changes to DNS*: The DNS Provider applies the changes to the zone. 18. *DNS Provider Redirects or User Flow Termination*: The DNS Provider either redirects the user agent back to the Service Provider or gracefully terminates the user flow. 19. *Service Provider Queries DNS Records*: The Service Provider queries the DNS records to verify that the changes have been applied. 20. *DNS Server Returns New DNS Records*: The DNS Server returns the updated DNS records. 21. *Service Provider Reports Success*: The Service Provider reports to the user that the domain has been successfully connected to the service. 6. Domain Connect Objects and Templates 6.1. Template Definition A template is defined as a standard JSON data structure containing the following data. Field values MUST be defined unless otherwise indicated. +=============+========+===================+========================+ |Data Element |Type |Key |Description | +=============+========+===================+========================+ |*Service |String |providerId |(REQUIRED) The unique | |Provider Id* | | |identifier of the | | | | |Service Provider that | | | | |created this template. | | | | |This is used in the URLs| Kowalik, et al. Expires 7 December 2026 [Page 15] Internet-Draft Domain Connect June 2026 | | | |to identify the Service | | | | |Provider. | | | | |The value MUST conform | | | | |to the dc-id syntax (see| | | | |Section 3). | | | | |To ensure non- | | | | |coordinated uniqueness, | | | | |this SHOULD be the | | | | |domain name of the | | | | |Service Provider (e.g. | | | | |exampleservice.example).| +-------------+--------+-------------------+------------------------+ |*Service |String |providerName |(REQUIRED) The name of | |Provider | | |the Service Provider, | |Name* | | |suitable for display to | | | | |the user. | | | | |The value MUST conform | | | | |to the dc-display-name | | | | |syntax (see Section 3). | +-------------+--------+-------------------+------------------------+ |*Service Id* |String |serviceId |(REQUIRED) The name or | | | | |identifier of the | | | | |template. This is used | | | | |in URLs to identify the | | | | |template. | | | | |The value MUST conform | | | | |to the dc-id syntax (see| | | | |Section 3). | +-------------+--------+-------------------+------------------------+ |*Service |String |serviceName |(REQUIRED) The name of | |Name* | | |the service, suitable | | | | |for display to the user.| | | | |The value MUST conform | | | | |to the dc-display-name | | | | |syntax (see Section 3). | +-------------+--------+-------------------+------------------------+ |*Version* |Integer |version |(OPTIONAL) If present | | | | |this represents a | | | | |version of the template | | | | |and SHOULD be changed | | | | |with each update of the | | | | |template content. This | | | | |opaque value is mainly | | | | |informational to improve| | | | |communication and | | | | |transparency between | | | | |providers. | | | | |The value MUST conform | Kowalik, et al. Expires 7 December 2026 [Page 16] Internet-Draft Domain Connect June 2026 | | | |to the dc-version syntax| | | | |(see Section 3). | | | | |This is a strict subset | | | | |of the "JSON number": a | | | | |positive integer with no| | | | |leading zeros, no | | | | |fractional part, and no | | | | |exponent part. | +-------------+--------+-------------------+------------------------+ |*Logo* |String |logoUrl |(OPTIONAL) A graphical | | | | |logo representing the | | | | |Service Provider and/or | | | | |Service for use in any | | | | |web-based flow. If | | | | |present this MAY be | | | | |displayed to the user on| | | | |the DNS Provider consent| | | | |UX. | | | | |When present, the value | | | | |MUST be a valid URI | | | | |[RFC3986] with scheme | | | | |"https". | +-------------+--------+-------------------+------------------------+ |*Description*|String |description |(OPTIONAL) A textual | | | | |description of what this| | | | |template does, intended | | | | |for developer reference.| | | | |This value is not | | | | |intended for display to | | | | |the end user. | | | | |The value MUST conform | | | | |to the dc-description- | | | | |text syntax (see | | | | |Section 3). | +-------------+--------+-------------------+------------------------+ |*Variable |String |variableDescription|(OPTIONAL) A textual | |Description* | | |description of the | | | | |template variables, | | | | |intended for developer | | | | |reference. This value | | | | |is not intended for | | | | |display to the end user.| | | | |The value MUST conform | | | | |to the dc-description- | | | | |text syntax (see | | | | |Section 3). | +-------------+--------+-------------------+------------------------+ |*Synchronous |Boolean |syncBlock |(OPTIONAL) When "true", | Kowalik, et al. Expires 7 December 2026 [Page 17] Internet-Draft Domain Connect June 2026 |Block* | | |indicates that this | | | | |template does not | | | | |support the synchronous | | | | |flow. The DNS Provider | | | | |MUST refuse a | | | | |synchronous apply | | | | |request for this | | | | |template and MUST return| | | | |an appropriate error to | | | | |the user. | | | | |The default is "false". | +-------------+--------+-------------------+------------------------+ |*Shared* |Boolean |shared |(OPTIONAL) This flag has| | | | |been deprecated. It | | | | |used to indicate that | | | | |the template allowed a | | | | |dynamic "providerName" | | | | |on the query string. It| | | | |is replaced with the | | | | |"sharedProviderName" | | | | |flag in v2.2 of the | | | | |spec. | +-------------+--------+-------------------+------------------------+ |*Shared |Boolean |sharedProviderName |(OPTIONAL) When "true", | |Provider | | |indicates that the | |Name* | | |caller MAY supply an | | | | |additional | | | | |"providerName" parameter| | | | |at apply time. | | | | |The default is "false". | | | | |For backward | | | | |compatibility with DNS | | | | |Providers prior to v2.2,| | | | |it is RECOMMENDED that | | | | |the deprecated "shared" | | | | |flag also be set. | +-------------+--------+-------------------+------------------------+ |*Shared |Boolean |sharedServiceName |(OPTIONAL) When "true", | |Service Name*| | |indicates that the | | | | |caller MAY supply an | | | | |additional "serviceName"| | | | |parameter at apply time.| | | | |The default is "false". | +-------------+--------+-------------------+------------------------+ |*Synchronous |String |syncPubKeyDomain |(OPTIONAL) The domain | |Public Key | | |name under which the | |Domain* | | |Service Provider's | | | | |public signing key TXT | Kowalik, et al. Expires 7 December 2026 [Page 18] Internet-Draft Domain Connect June 2026 | | | |record is published. | | | | |When present, this field| | | | |signals that digital | | | | |signing is required for | | | | |synchronous apply | | | | |requests. | | | | |The value MUST conform | | | | |to the dc-pubkey-domain | | | | |syntax (see Section 3). | +-------------+--------+-------------------+------------------------+ |*Synchronous |String |syncRedirectDomain |(OPTIONAL) A comma- | |Redirect | | |separated list of domain| |Domains* | | |names to which the DNS | | | | |Provider is permitted to| | | | |send the post-apply | | | | |redirect in the | | | | |synchronous flow. | | | | |The value MUST conform | | | | |to the "dc-host-list" | | | | |syntax (see Section 3). | +-------------+--------+-------------------+------------------------+ |*Multiple |Boolean |multiInstance |(OPTIONAL) When "true", | |Instance* | | |indicates that the | | | | |template is designed to | | | | |be applied multiple | | | | |times to the same domain| | | | |and host. | | | | |The default is "false". | +-------------+--------+-------------------+------------------------+ |*Warn |Boolean |warnPhishing |(OPTIONAL) When "true", | |Phishing* | | |signals that the | | | | |template contains | | | | |variables that cannot be| | | | |constrained by digital | | | | |signing and may be | | | | |susceptible to phishing.| | | | |The default is "false". | +-------------+--------+-------------------+------------------------+ |*Host |Boolean |hostRequired |(OPTIONAL) When "true", | |Required* | | |indicates that the | | | | |template is designed to | | | | |work only when both | | | | |"domain" and "host" | | | | |apply parameters are | | | | |provided, for example | | | | |when the template | | | | |contains a CNAME record | | | | |targeted at the fully | Kowalik, et al. Expires 7 December 2026 [Page 19] Internet-Draft Domain Connect June 2026 | | | |qualified domain name. | | | | |The default is "false". | +-------------+--------+-------------------+------------------------+ |*Template |Array of|records |(REQUIRED) A list of | |Records* |Template| |records for the | | |Records | |template. | +-------------+--------+-------------------+------------------------+ Table 1: properties of the template definition 6.2. Template Record Each template record is an entry that contains a type and several other values depending on the type. Many of these values can contain variables, which are expressed as strings surrounded with "%" or special variable "@" (See: Section 9.1). Variables are replaced with values when the template is applied. Each record MUST contain the following elements unless otherwise specified. +===========+======+=========================+======================+ |Data |Type |Key |Description | |Element | | | | +===========+======+=========================+======================+ |*Type* |enum |type |(REQUIRED) Describes | | | | |the type of record in | | | | |DNS, or the operation | | | | |impacting DNS. | | | | |Valid values include: | | | | |A, AAAA, CNAME, MX, | | | | |TXT, SRV, or SPFM. | | | | |The DNS Provider MUST | | | | |support the core set | | | | |of records A, AAAA, | | | | |CNAME, MX, TXT, SRV. | | | | |The DNS Provider | | | | |SHOULD support SPFM | | | | |record for high | | | | |interoperability with | | | | |existing templates | | | | | | | | | |All other record types| | | | |MAY be specified by | | | | |type name as listed in| | | | |IANA registry for DNS | Kowalik, et al. Expires 7 December 2026 [Page 20] Internet-Draft Domain Connect June 2026 | | | |Resource Record (RR) | | | | |TYPEs. Unknown record| | | | |types MAY be specified| | | | |as per [RFC3597] by | | | | |the word "TYPE" | | | | |immediately followed | | | | |by the decimal RR type| | | | |number, with no | | | | |intervening | | | | |whitespace. Support | | | | |for other record types| | | | |is OPTIONAL. | | | | |The value MUST conform| | | | |to the dc-record-type | | | | |syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Group ID* |String|groupId |(OPTIONAL) This | | | | |parameter identifies | | | | |the group the record | | | | |belongs to when | | | | |applying changes. The| | | | |value MUST conform to | | | | |the dc-id syntax (see | | | | |Section 3) and MUST | | | | |NOT contain variable | | | | |expressions. | +-----------+------+-------------------------+----------------------+ |*Essential*|enum |essential |(OPTIONAL) This | | | | |parameter indicates | | | | |how the record is | | | | |treated during | | | | |conflict detection | | | | |with existing | | | | |templates. | | | | |If the DNS Provider is| | | | |not implementing | | | | |applied template state| | | | |in DNS this is | | | | |ignored. | | | | |Always (default) - | | | | |record MUST be applied| | | | |and kept with the | | | | |template | | | | |OnApply - record MUST | | | | |be applied but can be | | | | |later removed without | | | | |dropping the whole | Kowalik, et al. Expires 7 December 2026 [Page 21] Internet-Draft Domain Connect June 2026 | | | |template | | | | |The value MUST conform| | | | |to the dc-essential | | | | |syntax (see | | | | |Section 3). | | | | |If omitted, the value | | | | |MUST be assumed to be | | | | |"Always". | +-----------+------+-------------------------+----------------------+ |*Host* |String|host |(REQUIRED) The host | | | | |for A, AAAA, CNAME, | | | | |NS, TXT, MX and other | | | | |unspecified record | | | | |type values. | | | | |This value is relative| | | | |to the applied host | | | | |and domain, unless | | | | |trailed by a ".". | | | | |A value of empty or | | | | |"@" indicates the root| | | | |of the applied host | | | | |and domain. In other | | | | |words | | | | |"[host.]example.com.".| | | | |When used in a | | | | |template definition, | | | | |the value MUST conform| | | | |to the dc-host-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the domain-| | | | |name syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Name* |String|name |The name for the SRV | | | | |record. | | | | |This value is relative| | | | |to the applied host | | | | |and domain. A value | | | | |of empty or "@" | | | | |indicates the root of | | | | |the applied host and | | | | |domain. | | | | |When used in a | | | | |template definition, | Kowalik, et al. Expires 7 December 2026 [Page 22] Internet-Draft Domain Connect June 2026 | | | |the value MUST conform| | | | |to the dc-host-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the domain-| | | | |name syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Points To*|String|pointsTo |The pointsTo location | | | | |for A, AAAA, CNAME, NS| | | | |and MX records. | | | | |When used in a | | | | |template definition, | | | | |the value MUST conform| | | | |to the "dc-pointsto- | | | | |tmpl" syntax for | | | | |"CNAME"/"MX" and to | | | | |the "dc-pointsto-nat- | | | | |tmpl" syntax for | | | | |A/AAAA/NS (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the | | | | |presentation format of| | | | |the corresponding | | | | |resource record type. | +-----------+------+-------------------------+----------------------+ |*TTL* |Int or|ttl |The time-to-live for | | |string| |the record in DNS. | | |repr. | |Valid for A, AAAA, | | |of Int| |CNAME, NS, TXT, MX, | | | | |and SRV records. This| | | | |SHOULD NOT contain | | | | |variables unless | | | | |absolutely necessary. | | | | |When used in a | | | | |template definition, | | | | |the value MUST conform| | | | |to the dc-ttl-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | Kowalik, et al. Expires 7 December 2026 [Page 23] Internet-Draft Domain Connect June 2026 | | | |resolved value MUST | | | | |conform to the dc-ttl-| | | | |value syntax. This | | | | |value, no matter if | | | | |variable or constant, | | | | |is understood as "best| | | | |effort" by DNS | | | | |Provider and MAY be | | | | |limited or adjusted by| | | | |local policy at | | | | |runtime or during | | | | |template onboarding, | | | | |like applying a | | | | |certain minimum or | | | | |maximum value of TTL | | | | |or an enumeration of | | | | |TTL values supported | | | | |by the DNS Provider. | | | | |The DNS Provider | | | | |SHOULD NOT reject | | | | |template application | | | | |because of invalid | | | | |value, rather pick the| | | | |nearest supported | | | | |value or a default, in| | | | |order to avoid | | | | |necessity of per | | | | |provider adjustment to| | | | |the application flow. | | | | |Support of variables | | | | |in this field is | | | | |OPTIONAL for DNS | | | | |Provider. | +-----------+------+-------------------------+----------------------+ |*Data* |String|data |For TXT record "data" | | | | |contains TXT-DATA | | | | |[RFC1035] in | | | | |presentation format. | | | | |For a single | | | | |"" | | | | |the heading and | | | | |trailing " character | | | | |MAY be omitted even if| | | | |space character is | | | | |present in the value. | | | | |"data" MUST NOT be | | | | |present in a template | | | | |record for any other | Kowalik, et al. Expires 7 December 2026 [Page 24] Internet-Draft Domain Connect June 2026 | | | |record type that has | | | | |type-specific data | | | | |fields defined in this| | | | |specification. For | | | | |any unspecified record| | | | |type, this field | | | | |contains the canonical| | | | |presentation format of| | | | |the record, following | | | | |[RFC3597] generic or | | | | |type-specific | | | | |encoding. | +-----------+------+-------------------------+----------------------+ |*TXT |String|txtConflictMatchingMode |Describes how | |Conflict | | |conflicts on the TXT | |Matching | | |record are detected. | |Mode* | | |Possible values are | | | | |None, All, or Prefix. | | | | |See below | | | | |(Section 10.4). | | | | |The value MUST conform| | | | |to the dc-txt- | | | | |conflict-mode syntax | | | | |(see Section 3). | | | | |If omitted, the value | | | | |MUST be assumed to be | | | | |"None". | +-----------+------+-------------------------+----------------------+ |*TXT |String|txtConflictMatchingPrefix|The prefix to detect | |Conflict | | |conflicts when | |Matching | | |txtConflict- | |Prefix* | | |MatchingMode is | | | | |"Prefix". See below | | | | |(Section 10.4). | | | | |The value MUST conform| | | | |to the dc-conflict- | | | | |prefix syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Priority* |Int or|priority |The priority for an MX| | |string| |or SRV record. | | |repr. | |When used in a | | |of Int| |template definition, | | | | |the value MUST conform| | | | |to the dc-uint16-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | Kowalik, et al. Expires 7 December 2026 [Page 25] Internet-Draft Domain Connect June 2026 | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the dc- | | | | |uint16-value syntax. | | | | |Support of variables | | | | |in this field is | | | | |OPTIONAL for DNS | | | | |Provider. | +-----------+------+-------------------------+----------------------+ |*Weight* |Int or|weight |The weight for the SRV| | |string| |record. | | |repr. | |When used in a | | |of Int| |template definition, | | | | |the value MUST conform| | | | |to the dc-uint16-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the dc- | | | | |uint16-value syntax. | | | | |Support of variables | | | | |in this field is | | | | |OPTIONAL for DNS | | | | |Provider. | +-----------+------+-------------------------+----------------------+ |*Port* |Int or|port |The port for the SRV | | |string| |record. | | |repr. | |When used in a | | |of Int| |template definition, | | | | |the value MUST conform| | | | |to the dc-uint16-tmpl | | | | |syntax (see | | | | |Section 3). | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the dc- | | | | |uint16-value syntax. | | | | |The resolved value is | | | | |further constrained to| | | | |the range 0-65535 as | | | | |defined by [RFC6335]. | | | | |Support of variables | | | | |in this field is | | | | |OPTIONAL for DNS | | | | |Provider. | Kowalik, et al. Expires 7 December 2026 [Page 26] Internet-Draft Domain Connect June 2026 +-----------+------+-------------------------+----------------------+ |*Protocol* |String|protocol |The protocol for the | | | | |SRV record. | | | | |The value MUST conform| | | | |to the dc-srv-protocol| | | | |syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Service* |String|service |The symbolic service | | | | |name for the SRV | | | | |record. | | | | |The value MUST conform| | | | |to the dc-srv-service | | | | |syntax (see | | | | |Section 3). | +-----------+------+-------------------------+----------------------+ |*Target* |String|target |The target hostname | | | | |for the SRV record as | | | | |defined in Section 3.1| | | | |of [RFC2782]. | | | | |When used in a | | | | |template definition, | | | | |the value MUST conform| | | | |to the dc-pointsto- | | | | |tmpl syntax (see | | | | |Section 3), or be the | | | | |single label "." to | | | | |indicate that the | | | | |service is not | | | | |available. | | | | |After variable | | | | |substitution, the | | | | |resolved value MUST | | | | |conform to the domain-| | | | |name syntax (see | | | | |Section 3), or be ".".| +-----------+------+-------------------------+----------------------+ |*SPF Rules*|String|spfRules |These are desired | | | | |rules for the SPF TXT | | | | |record. These rules | | | | |SHOULD be merged with | | | | |other SPFM records | | | | |into final SPF TXT | | | | |record. See | | | | |Section 9.4. The | | | | |value MUST contain | | | | |only mechanism and | | | | |modifier terms as | Kowalik, et al. Expires 7 December 2026 [Page 27] Internet-Draft Domain Connect June 2026 | | | |defined in [RFC7208] | | | | |Section 5, excluding | | | | |the version prefix | | | | |("v=spf1") and the | | | | |terminating "all" | | | | |qualifier. The DNS | | | | |Provider MUST validate| | | | |the syntax before | | | | |merging. | +-----------+------+-------------------------+----------------------+ Table 2: properties of the template record definition The following table lists the fields that MAY be defined for each record type. Other fields MUST NOT be used. +=========+========================================================+ | Type | Required fields | +=========+========================================================+ | "A" | "host", "pointsTo", "ttl" | +---------+--------------------------------------------------------+ | "AAAA" | "host", "pointsTo", "ttl" | +---------+--------------------------------------------------------+ | "CNAME" | "host", "pointsTo", "ttl" ("host" MUST NOT be "@" or | | | empty unless "hostRequired" is "true" in the template) | +---------+--------------------------------------------------------+ | "NS" | "host", "pointsTo", "ttl" | +---------+--------------------------------------------------------+ | "TXT" | "host", "data", "ttl", "txtConflictMatchingMode", | | | "txtConflictMatchingPrefix" | +---------+--------------------------------------------------------+ | "MX" | "host", "pointsTo", "ttl", "priority" | +---------+--------------------------------------------------------+ | "SRV" | "name", "target", "ttl", "priority", "protocol", | | | "service", "weight", "port" | +---------+--------------------------------------------------------+ | "SPFM" | "host", "spfRules" | +---------+--------------------------------------------------------+ | other | "host", "data", "ttl" | | types | | +---------+--------------------------------------------------------+ Table 3: Fields per record type 6.3. Template Considerations Kowalik, et al. Expires 7 December 2026 [Page 28] Internet-Draft Domain Connect June 2026 6.3.1. Template Scope Templates MUST be considered as scoped to the "domain" and "host" apply parameter pair. The "host" value is specified in the apply URL. The template's "host" or "name" field values are interpreted relative to this scope, as described in Section 9.3. 6.3.2. Sub Domains The recommended way to configure records on a Sub Domain is to use the "host" apply parameter rather than embedding sub-domain labels in template "host" field values as variables. This keeps the template scope unambiguous and enables correct conflict detection and template state tracking. Template "host" field values containing variables that resolve to sub-domain labels cause the template scope to be indeterminate at consent time, which prevents accurate conflict detection. To add a record at the Zone Apex even when a Sub Domain is specified in the apply request, the template "host" field value "%domain%." MAY be used, which resolves to the absolute Zone Apex name regardless of the "host" parameter. When a template is not applicable at the Zone Apex - for example because it contains a CNAME record or any other record type that is incompatible with Apex placement - the "hostRequired" flag SHOULD be set to "true" in the template definition (see hostRequired (Section 6.1)). 6.3.3. Variable Scope Minimisation It is noted that as a best practice the variable portions SHOULD be constrained to as small as possible a portion of the resulting DNS record. For example, say a Service Provider requires a CNAME of one of three values for their users: "s01.example.com", "s02.example.com", and "s03.example.com". The value in the template could simply contain "%servercluster%", and the fully qualified string passed in. Alternatively, the value in the template could contain "%var%.example.com" and a value of "01", "02", or "03" passed in. By placing more fixed data into the template, the template is less prone to error or misuse and allows better review of intent by the DNS Provider when onboarding the template. Kowalik, et al. Expires 7 December 2026 [Page 29] Internet-Draft Domain Connect June 2026 6.4. Public Key Publication The Service Provider MUST publish their public signing key in one or more DNS TXT records at the host formed by prepending the "key" apply parameter value as a label to the "syncPubKeyDomain" template field value. Each TXT record MUST conform to the following grammar: dc-pubkey-record = dc-pubkey-kv *( "," dc-pubkey-kv ) dc-pubkey-kv = ( "p" "=" dc-frag-index ) / ( "d" "=" dc-frag-data ) / ( "a" "=" dc-alg-id ) / ( "t" "=" dc-key-type ) dc-frag-index = 1*DIGIT ; positive decimal integer; ; used for p= dc-frag-data = 1*( ALPHA / DIGIT / "+" / "/" / "=" ) ; standard base64 per RFC 4648; ; used for d= dc-alg-id = 1*( ALPHA / DIGIT / "-" ) ; JWS algorithm identifier per RFC 7518; ; used for a= dc-key-type = 1*( ALPHA / DIGIT / "-" ) ; public key format identifier; ; used for t= Kowalik, et al. Expires 7 December 2026 [Page 30] Internet-Draft Domain Connect June 2026 +============+=====+================================================+ | Property | Key | Description | +============+=====+================================================+ | *Fragment | p | (REQUIRED) The sequence number of this key | | Index* | | fragment. | | | | The value MUST conform to the dc-frag- | | | | index rule above: a positive decimal | | | | integer. | | | | Fragments MUST be reassembled in ascending | | | | numeric order of "p". | +------------+-----+------------------------------------------------+ | *Fragment | d | (REQUIRED) A Fragment of base64-encoded | | Payload* | | key material. | | | | The value MUST conform to the dc-frag-data | | | | rule above: standard base64 encoding per | | | | [RFC4648]. | +------------+-----+------------------------------------------------+ | *Signing | a | (OPTIONAL) The JWS algorithm identifier | | Algorithm* | | for the signing algorithm. | | | | The value MUST conform to the dc-alg-id | | | | rule above and MUST be registered in the | | | | IANA "JSON Web Signature and Encryption | | | | Algorithms" registry established by | | | | [RFC7518]. | | | | If omitted, MUST be assumed to be "RS256". | | | | Support for "RS256" is MANDATORY for both | | | | DNS Providers and Service Providers. | +------------+-----+------------------------------------------------+ | *Public | t | (OPTIONAL) The format of the public key. | | Key | | The value MUST conform to the dc-key-type | | Format* | | rule above. | | | | If omitted, MUST be assumed to be "x509". | +------------+-----+------------------------------------------------+ Table 4: Properties of the public key TXT record To allow for key rotation or use of multiple keys, the Service Provider MAY publish key records at multiple hosts within "syncPubKeyDomain". The "key" apply parameter identifies which host to query for each request and MUST be included in the signed apply request. To account for DNS record size limits, a public key MAY be split across multiple TXT records at the same host. All fragments MUST be reassembled in ascending numeric order of "p" before use. The values "a" and '"d"' MUST be equal for all such TXT records on the same host. Kowalik, et al. Expires 7 December 2026 [Page 31] Internet-Draft Domain Connect June 2026 Given the public key (line breaks for brevity): MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA18SgvpmeasN4BHkkv0SBjAzIc 4grYLjiAXRtNiBUiGUDMeTzQrKTsWvy9NuxU1dIHCZy9o1CrKNg5EzLIZLNyMfI6qiXnM +HMd4byp97zs/3D39Q8iR5poubQcRaGozWx8yQpG0OcVdmEVcTfyR/XSEWC5u16EBNvRn NAOAvZYUdWqVyQvXsjnxQot8KcK0QP8iHpoL/1dbdRy2opRPQ2FdZpovUgknybq/6FkeD tW7uCQ6Mvu4QxcUa3+WP9nYHKtgWip/eFxpeb+qLvcLHf1h0JXtxLVdyy6OLk3f2JRYUX 2ZZVDvG3biTpeJz6iRzjGg6MfGxXZHjI8weDjXrJwIDAQAB Published at "_dcpubkeyv1." as (line breaks for brevity): EXAMPLE: Example: public key published as DNS TXT records p=1,a=RS256,d=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA18SgvpmeasN 4BHkkv0SBjAzIc4grYLjiAXRtNiBUiGUDMeTzQrKTsWvy9NuxU1dIHCZy9o1CrKNg5EzL IZLNyMfI6qiXnM+HMd4byp97zs/3D39Q8iR5poubQcRaGozWx8yQpG0OcVdmEVcTfy p=2,a=RS256,d=R/XSEWC5u16EBNvRnNAOAvZYUdWqVyQvXsjnxQot8KcK0QP8iHpoL/1 dbdRy2opRPQ2FdZpovUgknybq/6FkeDtW7uCQ6Mvu4QxcUa3+WP9nYHKtgWip/eFxpeb+ qLvcLHf1h0JXtxLVdyy6OLk3f2JRYUX2ZZVDvG3biTpeJz6iRzjGg6MfGxXZHjI8 p=3,a=RS256,d=weDjXrJwIDAQAB 7. DNS Provider Discovery To facilitate discovery of the DNS Provider from a domain name DNS is utilized. This is done by returning a TXT record for "_domainconnect" in the zone. The record content represents an authority and path part of the settings REST API URL. EXAMPLE 1: An example of the contents of this record: domainconnect.virtucondomains.example "_domainconnect" TXT record content, when prepended with https:// schema and appended with /v2 path segment, MUST form a valid URL [RFC3986]. "_domainconnect" TXT record MUST contain the authority part of the URL and MAY contain a path part. "_domainconnect" MUST not contain schema, query or fragment part of an URL. As a practical matter of implementation, the DNS Provider may or may not contain a copy of this data in each and every zone. Instead, the DNS Provider MUST simply respond to the DNS query for the "_domainconnect" TXT record with the appropriate data. Kowalik, et al. Expires 7 December 2026 [Page 32] Internet-Draft Domain Connect June 2026 How this is implemented is up to the DNS Provider. For example, the DNS Provider may not store the data inside a TXT record for the domain, opting instead to put a CNAME in the zone and have the TXT record in the target of the CNAME. Another DNS Provider may simply respond with the appropriate records at the DNS layer without having the data in each zone. The URL prefix returned MUST be subsequently used by the Service Provider to determine the additional settings for using Domain Connect on this domain at the DNS Provider. This is done by calling a REST API. Normative URI template of the Settings End-Point per [RFC6570]: GET https://{+_domainconnect}/v2/{domain}/settings "_domainconnect" parameter is the URL prefix returned in the "_domainconnect" TXT record. This MUST return a JSON structure containing the settings to use for Domain Connect on the domain name (passed in on the path) at the DNS Provider. This JSON structure MUST contain the following fields unless otherwise specified. +==============+=====================+========+=====================+ | *Field* | *Key* | *Type* | *Description* | +==============+=====================+========+=====================+ | *Provider | providerId | String | (REQUIRED) Unique | | Id* | | | identifier for the | | | | | DNS Provider. | | | | | The value MUST | | | | | conform to the dc- | | | | | id syntax (see | | | | | Section 3). | | | | | To allow for non- | | | | | coordinated | | | | | uniqueness, this | | | | | SHOULD be the | | | | | domain name of the | | | | | DNS Provider (e.g. | | | | | virtucom.example). | +--------------+---------------------+--------+---------------------+ | *Provider | providerName | String | (REQUIRED) The | | Name* | | | name of the DNS | | | | | Provider. | Kowalik, et al. Expires 7 December 2026 [Page 33] Internet-Draft Domain Connect June 2026 | | | | The value MUST | | | | | conform to the dc- | | | | | display-name | | | | | syntax (see | | | | | Section 3). | +--------------+---------------------+--------+---------------------+ | *Provider | providerDisplayName | String | (OPTIONAL) The | | Display | | | name of the DNS | | Name* | | | Provider that | | | | | SHOULD be | | | | | displayed by the | | | | | Service Provider. | | | | | This MAY change | | | | | per domain for | | | | | some DNS Providers | | | | | that power | | | | | multiple brands. | | | | | When present, the | | | | | value MUST conform | | | | | to the dc-display- | | | | | name syntax (see | | | | | Section 3). | +--------------+---------------------+--------+---------------------+ | *UX URL | urlSyncUX | String | (OPTIONAL) The URL | | Prefix for | | | Prefix for linking | | Synchronous | | | to the UX of | | Flows* | | | Domain Connect for | | | | | the synchronous | | | | | flow at the DNS | | | | | Provider. If not | | | | | returned, the DNS | | | | | Provider is not | | | | | supporting the | | | | | synchronous flow | | | | | on this domain. | | | | | This MUST be a | | | | | valid URI | | | | | [RFC3986] with | | | | | scheme "https", | | | | | MUST include an | | | | | authority | | | | | component, and | | | | | MUST NOT contain a | | | | | query component or | | | | | fragment | | | | | component. | | | | | The URI MAY | | | | | include a path | Kowalik, et al. Expires 7 December 2026 [Page 34] Internet-Draft Domain Connect June 2026 | | | | component. | +--------------+---------------------+--------+---------------------+ | *UX URL | urlAsyncUX | String | (Reserved. See | | Prefix for | | | Section 3, | | Asynchronous | | | Paragraph 13.) | | Flows* | | | | +--------------+---------------------+--------+---------------------+ | *API URL | urlAPI | String | (REQUIRED) The URL | | Prefix* | | | Prefix for the | | | | | REST API. | | | | | This MUST be a | | | | | valid URI | | | | | [RFC3986] with | | | | | scheme "https", | | | | | MUST include an | | | | | authority | | | | | component, and | | | | | MUST NOT contain a | | | | | query component or | | | | | fragment | | | | | component. | | | | | The URI MAY | | | | | include a path | | | | | component. | +--------------+---------------------+--------+---------------------+ | *Width of | width | Number | (OPTIONAL) The | | Window* | | | desired width in | | | | | pixels of the pop- | | | | | up window used for | | | | | granting consent. | | | | | If not present, | | | | | the default MUST | | | | | be assumed to be | | | | | 750. | +--------------+---------------------+--------+---------------------+ | *Height of | height | Number | (OPTIONAL) The | | Window* | | | desired height in | | | | | pixels of the pop- | | | | | up window used for | | | | | granting consent. | | | | | If not present, | | | | | the default MUST | | | | | be assumed to be | | | | | 750. | +--------------+---------------------+--------+---------------------+ | *UX URL | urlControlPanel | String | (OPTIONAL) A URL | | Control | | | to the DNS | | Panel* | | | Provider's control | Kowalik, et al. Expires 7 December 2026 [Page 35] Internet-Draft Domain Connect June 2026 | | | | panel for manual | | | | | DNS editing. This | | | | | field allows a | | | | | Service Provider | | | | | whose template is | | | | | not supported at | | | | | the DNS Provider | | | | | to provide a | | | | | direct link to | | | | | perform manual | | | | | edits. | | | | | The value MAY | | | | | contain the | | | | | literal token | | | | | "%domain%" as a | | | | | placeholder for | | | | | the domain name, | | | | | to allow deep- | | | | | linking to a | | | | | specific domain. | | | | | The value, after | | | | | any substitution | | | | | of the "%domain%" | | | | | token, MUST be a | | | | | valid URI per | | | | | [RFC3986] with | | | | | scheme "https". | +--------------+---------------------+--------+---------------------+ | *Name | nameServers | List | (OPTIONAL) The | | Servers* | | of | list of nameserver | | | | String | hostnames for the | | | | | zone held by this | | | | | DNS Provider | | | | | (typically derived | | | | | from the zone's NS | | | | | records). | | | | | Each entry MUST | | | | | conform to the | | | | | "domain-name" | | | | | syntax (see | | | | | Section 3). | +--------------+---------------------+--------+---------------------+ Table 5: properties of the settings data structure Clients MUST ignore any JSON properties in the settings response that are not defined in this specification or not recognized from an applicable extension. DNS Providers MAY include additional JSON Kowalik, et al. Expires 7 December 2026 [Page 36] Internet-Draft Domain Connect June 2026 properties in the settings response beyond those defined in this specification, however it is RECOMMENDED that those properties are registered in the "Domain Connect Settings Properties" registry defined in Section 12.2 in order to avoid name conflicts. EXAMPLE 2: Example Settings End-Point response { "providerId": "virtucondomains.example", "providerName": "Virtucon Domains", "providerDisplayName": "Virtucon Domains", "urlSyncUX": "https://domainconnect.virtucondomains.example", "urlAsyncUX": "https://domainconnect.virtucondomains.example", "urlAPI": "https://api.domainconnect.virtucondomains.example", "width": 750, "height": 750, "urlControlPanel": "https://domaincontrolpanel.virtucondomains.ex ample/?domain=%domain%", "nameServers": ["ns01.virtucondomainsdns.example", "ns02.virtucon domainsdns.example"] } When constructing a deep link using "urlControlPanel", the Service Provider MUST replace any occurrence of the literal token "%domain%" with the percent-encoded ACE-form domain name per [RFC3986]. The "%domain%" token MUST be the only substitution token used. The Service Provider MAY compare the "nameServers" list against the authoritative nameservers obtained from the DNS registry or an authoritative NS query, to verify that the correct DNS Provider has been reached. A mismatch may indicate a stale or incorrect "_domainconnect" TXT record, or a deliberate administrative change such as pre-provisioning with a new DNS provider. Discovery MUST work on the Zone Apex only. Bear in mind that zones can be delegated to other users, making this information valuable to Service Providers since DNS changes may be different for a Zone Apex vs. a Sub Domain for an individual service. The Service Provider MUST handle the condition when a query for the "_domainconnect" TXT record succeeds, but a call to query for the JSON fails. This can happen if the zone is hosted with another DNS Provider, but contains an incorrect "_domainconnect" TXT record. The DNS Provider MUST return a 404 HTTP error code if they do not contain the zone. Kowalik, et al. Expires 7 December 2026 [Page 37] Internet-Draft Domain Connect June 2026 +===========+==========+===========================================+ | Status | Response | Description | +===========+==========+===========================================+ | *Success* | 2xx | A response of an http status code of 2xx | | | | indicates that the call was successful. | | | | The response is the JSON described above. | +-----------+----------+-------------------------------------------+ | *Not | 404 | A response of a 404 indicates that the | | Found* | | DNS Provider does not have the zone. | +-----------+----------+-------------------------------------------+ Table 6: HTTP status codes for the settings end-point 8. Applying Domain Connect 8.1. Endpoints The Domain Connect endpoints returned in the JSON during discovery are in the form of URLs. The first set of endpoints are for the UX that the Service Provider links to. These are for the synchronous flow where the user can click to grant consent and have changes applied. The second set of endpoints are for the REST API. All endpoints begin with a root URL for the DNS Provider such as: https://connect.dnsprovider.example They MAY also include any path segment at the discretion of the DNS Provider. For example: https://connect.dnsprovider.example/api The root URLs for the UX endpoints and the API endpoints are returned in the JSON payload during DNS Provider discovery. 8.2. Query Supported Template Normative URI template of the template query end-point per [RFC6570]: GET {+urlAPI}/v2/domainTemplates/providers/{providerId}/services /{serviceId} Kowalik, et al. Expires 7 December 2026 [Page 38] Internet-Draft Domain Connect June 2026 This URL is be used by the Service Provider to determine if the DNS Provider supports a specific template. The following table describes the parameters of the URI template: +==========+============+====================================+ | Property | Key | Description | +==========+============+====================================+ | *URL | urlAPI | (REQUIRED) The base URL of the DNS | | API* | | Provider API, taken from the | | | | "urlAPI" field of the settings | | | | endpoint response (see Section 7). | | | | This MUST be a valid URI [RFC3986] | | | | with scheme "https" | +----------+------------+------------------------------------+ | *Service | providerId | (REQUIRED) Identifier of the | | Provider | | Service Provider of the template. | | Id* | | The value MUST conform to the dc- | | | | id syntax (see Section 3). | +----------+------------+------------------------------------+ | *Service | serviceId | (REQUIRED) Identifier of the | | Id* | | template within the Service | | | | Provider's namespace. | | | | The value MUST conform to the dc- | | | | id syntax (see Section 3). | +----------+------------+------------------------------------+ Table 7: URI template parameters for the query supported template end-point Returning a status of 200 without a body indicates the template is supported. The DNS Provider MAY disclose the version of the template in a JSON object with field "version" (see: version field (Section 6.1) or the full JSON object of deployed template. Returning a status of 404 indicates the template is not supported. Kowalik, et al. Expires 7 December 2026 [Page 39] Internet-Draft Domain Connect June 2026 +===========+==========+======================================+ | Status | Response | Description | +===========+==========+======================================+ | *Success* | 2xx | A response of an http status code of | | | | 2xx indicates that the call was | | | | successful. The response OPTIONALLY | | | | contains the version or template. | +-----------+----------+--------------------------------------+ | *Not | 404 | A response of a 404 indicates that | | Found* | | the template is not supported | +-----------+----------+--------------------------------------+ Table 8: https status codes for the Query Supported Template end-point 8.3. Synchronous Flow 8.3.1. Apply Template URL Normative URI template of the synchronous template apply end-point per [RFC6570]: GET {+urlSyncUX}/v2/domainTemplates/providers/{providerId}/services /{serviceId}/apply{?domain,host,groupId,providerName, serviceName,instanceId,redirect_uri,properties*}{&sig,key} This is the URL, where the user agent is directed to apply a template to a dns zone the user controls. It is redirected to or linked from the Service Provider to start the synchronous Domain Connect Protocol. 8.3.2. Parameters/properties For "properties" name/value pairs, parameter names and values MUST be URL-decoded (percent-decoded per [RFC3986]) before processing. +=============+==============+===================================+ | Property | Request | Description | | | Parameter | | +=============+==============+===================================+ | *URL Sync | urlSyncUX | (REQUIRED) The base URL of the | | UX* | | DNS Provider synchronous UX | | | | endpoint, taken from the | | | | "urlSyncUX" field of the settings | | | | endpoint response (see | | | | Section 7). | Kowalik, et al. Expires 7 December 2026 [Page 40] Internet-Draft Domain Connect June 2026 | | | This MUST be a valid URI | | | | [RFC3986] with scheme "https" | +-------------+--------------+-----------------------------------+ | *Service | providerId | (REQUIRED) Identifier of the | | Provider | | Service Provider of the template | | Id* | | to be applied. The value MUST | | | | conform to the dc-id syntax (see | | | | Section 3). | +-------------+--------------+-----------------------------------+ | *Service | serviceId | (REQUIRED) Identifier of the | | Id* | | template to be applied. The | | | | value MUST conform to the dc-id | | | | syntax (see Section 3). | +-------------+--------------+-----------------------------------+ | *Domain* | domain | (REQUIRED) The domain name being | | | | configured. This is the Zone | | | | Apex (the registered domain or | | | | delegated zone). The value MUST | | | | conform to the domain-name syntax | | | | (see Section 3). | +-------------+--------------+-----------------------------------+ | *Host* | host | (OPTIONAL) The host name of the | | | | Sub Domain within the zone | | | | identified by "domain". | | | | When present, the value MUST be a | | | | single name conforming to domain- | | | | name (see Section 3) or an empty | | | | string. | +-------------+--------------+-----------------------------------+ | *Redirect | redirect_uri | (OPTIONAL) The location to direct | | URI* | | the user agent to upon successful | | | | authorization or upon error. | | | | The value MUST be an absolute URI | | | | conforming to [RFC3986]. | +-------------+--------------+-----------------------------------+ | *State* | state | (OPTIONAL) A random and unique | | | | string passed along to prevent | | | | CSRF, or to pass back state. | | | | The value MUST conform to the | | | | "state" syntax (see Section 3). | +-------------+--------------+-----------------------------------+ | *Name/Value | properties | (REQUIRED) Variable values to be | | Pairs* | | substituted into the template. | | | | Each parameter name MUST | | | | correspond to a variable name | | | | defined in the template and MUST | | | | conform to the variable-name | | | | syntax (see Section 3). | Kowalik, et al. Expires 7 December 2026 [Page 41] Internet-Draft Domain Connect June 2026 | | | Each parameter value MUST conform | | | | to the dc-prop-value syntax (see | | | | Section 3), using the DNS | | | | presentation format [RFC9499]. | | | | The parameter value corresponds | | | | to the value that will be used | | | | when applying the template. | +-------------+--------------+-----------------------------------+ | *Provider | providerName | (OPTIONAL) Additional display | | Name* | | text for the template | | | | "providerName", provided by the | | | | caller. If "sharedProviderName" | | | | is not set in the template, this | | | | parameter MUST NOT be set. Note: | | | | this used to be controlled by the | | | | "shared" attribute in the | | | | template, which has been | | | | deprecated. | | | | The value MUST conform to the dc- | | | | display-name syntax (see | | | | Section 3). | +-------------+--------------+-----------------------------------+ | *Service | serviceName | (OPTIONAL) Additional display | | Name* | | text for the template | | | | "serviceName", provided by the | | | | caller. If "sharedServiceName" | | | | is not set in the template, this | | | | parameter MUST NOT be set. | | | | The value MUST conform to the dc- | | | | display-name syntax (see | | | | Section 3). | +-------------+--------------+-----------------------------------+ | *Group ID* | groupId | (OPTIONAL) Specifies the subset | | | | of groups from the template to | | | | apply. | | | | The value MUST conform to the dc- | | | | id-list syntax (see Section 3). | +-------------+--------------+-----------------------------------+ | *Signature* | sig | (OPTIONAL) A digital signature of | | | | the canonical query string. The | | | | value MUST conform to the dc-sig | | | | syntax (see Section 3): | | | | a standard base64-encoded | | | | [RFC4648] signature, URL-encoded | | | | when carried in the query string. | | | | See the Section 8.3.2.1 below for | | | | the signing procedure. | +-------------+--------------+-----------------------------------+ Kowalik, et al. Expires 7 December 2026 [Page 42] Internet-Draft Domain Connect June 2026 | *Key* | key | (OPTIONAL) The DNS host label | | | | within the syncPubKeyDomain at | | | | which the public key TXT record | | | | is published. | | | | The value MUST conform to the dc- | | | | key-label syntax (see Section 3): | | | | a single DNS label, either a | | | | plain ACE-form label or an RFC | | | | 8552 underscore-prefixed label. | | | | See the Section 8.3.2.1 below. | +-------------+--------------+-----------------------------------+ Table 9: URI template parameters of the apply call in the sync flow An example query string: GET https://web-connect.dnsprovider.example/v2/domainTemplates/providers/ exampleservice.example/services/template1/apply?domain=example.com& IP=192.168.42.42&RANDOMTEXT=shm%3A1542108821%3AHello This call indicates that the Service Provider wishes to connect the domain example.com to the service using the template identified by the composite key of the provider (exampleservice.example) and the service template owned by them (template1). In this example, there are two variables in this template, "IP" and "RANDOMTEXT". These variables are passed as name/value pairs. 8.3.2.1. Signing Procedure Signing the query string is OPTIONAL for templates that do not specify "syncPubKeyDomain". When "syncPubKeyDomain" is present in the template, the Service Provider MUST sign the request and the DNS Provider MUST reject any unsigned apply request (see Section 8.3.4). The Service Provider MUST generate the digital signature as follows: 1. Construct the canonical input string: a. Take all apply parameters except "sig" and "key". b. URL-encode each parameter name and value per [RFC3986]. c. Sort the parameters in ascending lexicographic order of the URL-encoded parameter name. Kowalik, et al. Expires 7 December 2026 [Page 43] Internet-Draft Domain Connect June 2026 d. Concatenate them as name=value pairs joined by "&". 2. Sign the canonical input string using the private key corresponding to the public key published at the host identified by the "key" parameter within "syncPubKeyDomain" (see Section 6.4), using the algorithm identified by the "a" field of the key record (default: "RS256"). The "RS256" identifier denotes RSASSA-PKCS1-v1_5 using SHA-256, as defined in [RFC7518] Section 3.3. 3. The resulting signature MUST be Base64-encoded using the standard alphabet per [RFC4648] Section 4 (conforming to the dc-sig rule). 4. Append the URL-encoded "sig" value and the "key" identifier to the canonical input string to form a signed query string. The signed query string MUST be used as-is as the query string of the request URL, without re-encoding, adding or re-ordering of query parameters. EXAMPLE: Example: signed query string parameters Example canonical input: a=1&b=2&domain=example.net&ip=10.10.10.10&text=a%2Bb Example signature: sig=V2te9zWMU7G3plxBTsmYSJTvn2vzMvNwAjWQ%2BwTe91DxuJhdVf4cVc4vZBYfEYV 7u5d7PzTO7se7OrkhyiB7TpoJJW1yB5qHR7HKM5SZldUsdtg5%2B1SzEtIX0Uq8b2mCmQ F%2FuJGXpqCyFrEajvpTM7fFKPk1kuctmtkjV7%2BATcvNPLWY7KyE4%2Bqc8jpfN61cP 5l8iA4krAa3%2BfTro5cmWR8YUJ5yrnRs6KT4b5D71HFvOUk0sGEUddUUlsyRQKRHUFN6 HjEya50YDHfZJlYHkHlK0xX6Yqeii9QZ2I35U9eJbSvZGQko5beqviWFXdsVDbvd3DYcb SHgJq9%2FXoMTTw%3D%3D&key=_dcpubkeyv1 8.3.3. Template Apply Request The Service Provider initiates the synchronous flow by directing the user agent to the Apply Template URL (see Section 8.3.1), constructed as specified in Section 8.3.2. The DNS Provider validates the request to ensure that all required parameters are present and valid. This includes also verification of request signature (see Section 8.3.4 below). Kowalik, et al. Expires 7 December 2026 [Page 44] Internet-Draft Domain Connect June 2026 If the request is valid, the DNS Provider authenticates the user, validates user's authorization to modify the DNS zone, obtains authorization to apply the template to the DNS and finally applies the changes. This process is described in Section 10. 8.3.4. Signature Verification Upon receiving a Template Apply Request for a template whose "syncPubKeyDomain" is set, the DNS Provider MUST perform the following steps and MUST reject the request if any step fails: 1. *Check for required parameters* - The request MUST carry both "sig" and "key" parameters. 2. *Retrieve the public key* - Query DNS for TXT records at the host formed by prepending the "key" parameter value as a label to "syncPubKeyDomain" (see Section 6.4). If no such records are found, the processing fails. 3. *Reassemble key fragments* - Collect all TXT records at that host, parse each as a "dc-pubkey-record", and concatenate the "d" values in ascending order of "p" to obtain the complete encoded public key. 4. *Determine algorithm and key format* - Read the "a" and "t" fields. If absent, assume "RS256" and "x509" respectively. 5. *Decode the public key* - decode the key from Base64 encoding and key format indicated by "t". 6. *Construct the canonical input string* - Remove the "sig" and "key" key/value pairs from the received query string without reordering or re-encoding the remaining of the query string. If the canonical string needs to be reconstructed from individual parameters (what is not RECOMMENDED), the same construction steps as the signing procedure MUST be followed (see Section 8.3.2.1). 7. *Verify the signature* - URL-decode then base64-decode per [RFC4648] the "sig" parameter value, and verify the signature against the input string using the retrieved public key and identified algorithm. 8.3.5. Template Apply Response After successful processing of Template Apply Request the DNS Provider MUST terminate the user flow according to one of the following cases: Kowalik, et al. Expires 7 December 2026 [Page 45] Internet-Draft Domain Connect June 2026 * If "redirect_uri" was present in the request and the template's "syncRedirectDomain" field is set, the DNS Provider MUST redirect the user agent to the "redirect_uri". The following parameters MUST be appended to the "redirect_uri": - "state" - If a "state" parameter was present in the request, it MUST be echoed back unchanged as "state=" on the redirect URI. * If "redirect_uri" was not provided, or if "syncRedirectDomain" is not set in the template, the DNS Provider MUST gracefully terminate the user flow by other means (for example, displaying a completion page). When the user agent is a web browser and the DNS Provider's page was opened in a separate window or tab, the DNS Provider SHOULD attempt to close that window or tab. To prevent open redirects, the DNS Provider MUST NOT redirect the user agent to a "redirect_uri" value whose registered domain is not listed in the template's "syncRedirectDomain" field, unless the request carries a valid digital signature (see Section 8.3.2.1). The Service Provider SHOULD verify the outcome via DNS regardless of how the flow terminates (see Section 8.4). 8.3.6. Template Apply Error Response If the DNS Provider cannot complete the apply operation - for example because authentication failed, the user does not control the domain, the domain is suspended, or the user explicitly canceled - the DNS Provider MUST signal an error. If "redirect_uri" is present and the open-redirect constraint is satisfied, the DNS Provider MUST redirect the user agent to the "redirect_uri" with the following parameters appended: * "error" - REQUIRED on error. The value MUST be one of the error codes defined in Section 4.1.2.1 of [RFC6749]: "invalid_request", "unauthorized_client", "access_denied", "unsupported_response_type", "invalid_scope", "server_error", or "temporarily_unavailable". * "error_description" - OPTIONAL. A developer-oriented plain-text description of the error. The DNS Provider SHOULD keep descriptions vague where disclosure of internal account or domain state would be inappropriate. Kowalik, et al. Expires 7 December 2026 [Page 46] Internet-Draft Domain Connect June 2026 As a RECOMMENDED convention, when the user explicitly cancels the operation and the DNS Provider uses "error=access_denied", the "error_description" value MAY carry the prefix "user_cancel" to allow the Service Provider to distinguish user cancellation from other denial reasons. * "state" - If a "state" parameter was present in the request, it MUST be echoed back unchanged as "state=" on the redirect URI. If "redirect_uri" is not present or the open-redirect constraint is not satisfied, the DNS Provider MUST gracefully terminate the user flow and SHOULD present an appropriate error indication to the user. When the user agent is a web browser and the DNS Provider's page was opened in a separate window or tab, the DNS Provider SHOULD attempt to close that window or tab. 8.4. Verification of Changes After the synchronous flow completes, the Service Provider SHOULD verify that the expected DNS records are present in the zone by querying the authoritative DNS server for the domain. DNS verification MUST be treated as the authoritative signal of success. A "redirect_uri" callback received without an "error" parameter does not constitute proof that the template was applied. Users can modify redirect URIs in the user agent, so a successful- looking redirect MUST NOT be relied upon as confirmation of DNS changes. Similarly, a "redirect_uri" callback received with an "error" parameter does not constitute proof that the template was NOT applied; the DNS Provider MAY have applied the template before the error condition arose. Receipt of a protocol-level completion signal MAY be used as a trigger to initiate DNS verification. However, the Service Provider MUST account for DNS propagation delay and MUST implement a retry mechanism with appropriate intervals until the expected records are observed or a timeout is reached. To minimize delays caused by DNS resolver caching, it is RECOMMENDED that the Service Provider query a DNS resolver configured with low TTL overrides, or query the authoritative name servers directly. 9. Resolving Template Variables 9.1. Variables Kowalik, et al. Expires 7 December 2026 [Page 47] Internet-Draft Domain Connect June 2026 9.1.1. Variable Syntax Variable expressions are the parameterized parts of a Domain Connect Template. Each expression contains one variable specifier (which can be either a named variable or a special variable "@") that is replaced with a value during template application. Variable expressions MUST conform to "variable-expression" syntax (see Section 3). 9.1.2. Special and Built-In Variables There are three Built-In variables: * "%host%"`: This is the host passed from the query string * "%domain%"`: This is the domain passed from the query string * "%fqdn%": This is the fully qualified domain name or template application e.g. [host.]domain For example, with the query string "domain=example.com&host=", "%fqdn%" in a template would be "example.com", and with "domain=example.com&host=sub1", "%fqdn%" in a template would be "sub1.example.com". The "@" variable has special meaning, and can be used in the "host"/"name" field or in the "pointsTo" field in isolation. For the "host"/"name" and "pointsTo" fields it is a shortcut for the value "%fqdn%.". The trailing dot here is equal to the DNS master file notation [RFC1035], which indicates the value is absolute. For some record types, like "A" or "AAAA" usage of "@" in pointsTo would not render a valid IP address, therefore MUST NOT be used. Likewise in "NS" record types it would render a circular delegation therefore MUST NOT be used. 9.2. Variable substitution 9.2.1. Input Values * Template fields - the string-valued fields of each template record where variables are allowed. Fields MUST be decoded from JSON string encoding before variable substitution is performed. * Named variable values - the name/value pairs supplied by the caller in the apply request (query string parameters or JSON body). Values MUST be treated as strings regardless of how the underlying data source represents them; any transport encoding Kowalik, et al. Expires 7 December 2026 [Page 48] Internet-Draft Domain Connect June 2026 (e.g., URL percent-encoding) MUST be decoded before substitution. The resulting substituted value MUST reflect the exact original input value string. * Built-in variable values - the values of "%domain%", "%host%", and "%fqdn%" derived from the "domain" and "host" apply parameters (see Section 9.1.2). 9.2.2. Processing When a template is applied, the variables in the template are replaced with the values passed as input. Variables are identified by their name ('"variable-name"' part of the syntax or "@") and the whole variable expression is replaced with a value of either Built-In Variable or Name/Value pairs provided to the Apply operation. Only active records (as determined by group filtering, see Section 10.3) MUST be processed. Template fields of inactive records MUST NOT be processed. Variables are only allowed in template fields of type string, therefore the input field values from the template MUST be decoded from JSON string encoding before variable substitution. Variables are replaced in the template fields in the order they are found. If a variable is not found in the input, the processing MUST fail. After a variable is replaced, only the remaining string is used for further variable substitution. The result of the processing MAY still contain strings containing variable expressions coming from Input Values of variable substitution. The processing MUST NOT fail in this case, and the variable expressions MUST be left as is without any further processing. The DNS Provider MUST ignore any request parameter not referenced in the template. 9.3. Host Name Rendering After variable substitution, each template record's "host" or "name" field value is combined with the "domain" and "host" apply parameters to produce the final DNS owner name for the resource record. 9.3.1. Input Values Kowalik, et al. Expires 7 December 2026 [Page 49] Internet-Draft Domain Connect June 2026 * "domain" - the Zone Apex, as supplied in the apply request. * "host" - the Sub Domain label(s), as supplied in the apply request. An empty value or absence of this parameter indicates the Zone Apex. * The rendered "host" or "name" field value of the template record after variable substitution. 9.3.2. Processing If the rendered template field value is "@" or empty, it resolves to the root of the applied scope - equivalent to the fully qualified "[host.]domain.". If the rendered template field value ends with a "." (trailing dot), it is treated as an absolute DNS name and used as-is, without further qualification. Otherwise, the rendered value is treated as relative and prepended as a label to the fully qualified "[host.]domain" formed by the apply parameters. 9.3.3. Examples of host processing EXAMPLE: Template records example [{ "type": "CNAME", "host": "www", "pointsTo": "@", "ttl": 1800 }, { "type": "A", "host": "@", "pointsTo": "192.0.2.1", "ttl": 1800 }] DNS zone after the template applied with "domain=example.com" and "host" parameter missing or empty: www 1800 IN CNAME example.com. @ 1800 IN A 192.0.2.1 _alternatively_ Kowalik, et al. Expires 7 December 2026 [Page 50] Internet-Draft Domain Connect June 2026 www.example.com. 1800 IN CNAME example.com. example.com. 1800 IN A 192.0.2.1 DNS zone after the template applied with "domain=example.com" and "host=bar": www.bar 1800 IN CNAME bar.example.com. bar 1800 IN A 192.0.2.1 alternatively www.bar.example.com. 1800 IN CNAME bar.example.com. bar.example.com. 1800 IN A 192.0.2.1 9.4. SPF Record Merging The challenge with SPF RFC 7208 [RFC7208] records and Domain Connect is that an individual service might recommend an SPF record. If only one service were active, this would be accurate. But with several services together only the DNS Provider is able to determine the valid shape of a SPF TXT record. One solution to this problem is to merge all related records. At the highest level, this means taking everything between the "v=spf1" and the "all" from each of the records and merging them together, terminating with hard-coded modifier on "all" at the end. For an SPF record to fulfill it's purpose of protection against malicious email delivery, it is RECOMMENDED to use a fixed modifier "~" advising lower rating of the messages from other sources not specified in SPF, however DNS Provider MAY set this modifier at their own discretion and according to the current best practice. @ TXT v=spf1 include:spf.mailer1.example include:_spf.newsletter.exam ple ~all The other would be to write intermediate records, and reference these locally. r1.example.com. TXT v=spf1 include:spf.mailer1.example ~all r2.example.com. TXT v=spf1 include:_spf.newsletter.example ~all @ TXT v=spf1 include:r1.example.com include:r2.example.com ~all There are advantages and disadvantages to both approaches. SPF records have a limit of 10 DNS lookups and record length is limited to 255 characters. So depending on the embedded records both approaches might have advantages. Kowalik, et al. Expires 7 December 2026 [Page 51] Internet-Draft Domain Connect June 2026 The implementation would be left to the DNS Provider, but to facilitate this SPF records SHOULD NOT be included in templates. Instead, a new pseudo-record type is introduced in the template called "SPFM". This has the following attribute: "spfRules": Determines the desired rules, basically everything but leading "v=spf1" and trailing "all" rule - see: SPF Rules (Section 6.2) When a template is added or removed with an "SPFM" record in the template, some code would need to take the aggregate value of all "SPFM" records in all templates applied as well as existing SPF TXT record on the host and recalculate the resulting SPF TXT record. In case several sources specify the same rule with a different policy DNS Provider SHOULD apply the least restrictive one as a result. "soft failure" SHOULD be preferred over "hard failure", "neutral" SHOULD be preferred over "soft failure". DNS Provider SHOULD also allow the end user to modify the SPF record after merging. Due to merging step in between, the resulting SPF TXT records are considered non-essential. That means the user may decide to override the final calculated value or remove the whole SPF record. This action MUST NOT lead to removal of any related templates in conflict detection and template integrity routines if implemented by the DNS Provider. If the existing TXT record makes the merging operation not possible, the DNS Provider MUST handle this situation the same way as a conflict and either let the end-user resolve it in the UX. Service Providers MUST NOT check content of TXT SPF record for an exact match, as it might be strongly influenced by the DNS Provider merging strategy and user actions. See Appendix A.6. 10. Template Application 10.1. Template State in DNS Providers system DNS Providers MAY choose to maintain state inside records in DNS indicating the templates writing the records. Kowalik, et al. Expires 7 December 2026 [Page 52] Internet-Draft Domain Connect June 2026 A DNS Provider that maintains this state may be able to provide an improved experience for users, telling them the services enabled. They also may be able to have more advanced handling of conflicts and assure integrity of applied template instances. A template instance is identified by the pair "domain" and "host" where the template has been applied. Therefore, the same template MUST be able to be applied more than once to the same DNS zone identified by "domain", as long as the value of "host" parameter differs. Application of the same template with same "host" MAY be handled as an update by DNS provider, or just trigger a regular conflict detection and resolution routine by DNS Provider - removal of the previous instance and apply of the new instance. Manual changes made by the user at the DNS Provider MAY also trigger conflict detection against applied templates in order to maintain integrity. 10.2. Steps to Apply a Template The following steps give an overview of the template application process. Each step is described in detail in the sections below. 1. *Verify template applicability* - For synchronous flow requests, the DNS Provider MUST verify that the template's "syncBlock" field is not "true". If it is, the DNS Provider MUST NOT process the request and MUST return an error. 2. *Verify zone ownership* - The DNS Provider MUST verify that the target zone identified by "domain" is present in the user's account and that the user is authorized to make changes to it. 3. *Filter records to apply* - select records applicable for further processing based on "groupId" property of the template and "groupId" apply parameter (see Section 10.3). 4. *Resolve variables* - All variable expressions in active template records are substituted with the values provided by the caller, producing a concrete set of DNS resource records (RRs) to be applied (see Section 9.2). a. abort if rendered RRs are not possible to be applied to the target zone 5. *Perform conflict detection* - The DNS Provider checks the resolved RR set against the existing zone content according to the conflict detection rules (see Section 10.4). Kowalik, et al. Expires 7 December 2026 [Page 53] Internet-Draft Domain Connect June 2026 a. Identify individual zone records that conflict with the resolved RR set. b. (only DNS Providers tracking template state): Check each resolved RR against essential records of previously applied templates. Identify which previously applied templates own conflicting records and would be removed in their entirety (see Section 10.4.1.2). c. (only DNS Providers tracking template state): Mark instances of the same template applied on the same "host" for removal unless "multiInstance" is set for the template (see Section 10.4.1.1). 6. *Pre-calculate conflict resolution* - Determine the full set of records and, where applicable, template instances that would be removed upon application (see Section 10.5). 7. *Obtain user authorization* - The DNS Provider MUST present the intended changes and the pre-calculated conflict consequences to the user and obtain explicit authorization before proceeding (see Section 10.6). a. abort if authorization not granted 8. *Apply changes* - After authorization is granted, or at later point in Asynchronous flow: a. Remove all records pre-calculated for removal from the zone. b. Write the resolved RR set to the zone in totality. c. (only DNS Providers tracking template state): Record the new template instance for the "domain" and "host" pair and remove the state of any template instances that were resolved for removal. 10.3. Group Filtering Before variable substitution and any further processing, the DNS Provider MUST determine the *active record set* - the subset of template records that are subject to processing - by applying the following rules to each record in the template: 1. A record with no "groupId" field is always active, regardless of whether a "groupId" parameter was supplied in the apply request. Kowalik, et al. Expires 7 December 2026 [Page 54] Internet-Draft Domain Connect June 2026 2. A record with a "groupId" field is active if and only if its "groupId" value appears in the list supplied as the "groupId" apply parameter. Matching is case-sensitive and exact. 3. If no "groupId" parameter is supplied in the apply request, all records are active irrespective of whether they carry a "groupId". Only active records MUST be subject to variable substitution, conflict detection, and zone write operations. Inactive records MUST be excluded from all template processing steps and MUST NOT be written to the zone. If the "groupId" parameter is supplied but no record in the template carries a "groupId" that matches any of the specified identifiers (i.e., the active record set consists solely of ungrouped records or is empty), the DNS Provider MUST return an error and MUST NOT make any changes to the zone. 10.3.1. Group Filtering and Template State When a "groupId" parameter is supplied, the apply operation is additive: only the records belonging to the specified groups are written, while records of other groups that were written by a prior application of the same template instance MUST NOT be disturbed. Consequently, for DNS Providers that maintain applied template state, an existing instance of the same template on the same "domain" and "host" MUST NOT be removed before the new records are written, regardless of conflict-detection outcome for the active record set, however such provider MUST remove the records previously written for the same group(s) before writing the new active record set, in order to avoid accumulation of stale records from superseded group applications. 10.4. Conflict Detection Conflict detection is performed by the DNS Provider prior to template application. The rules below ensure predictable conflict resolution between DNS Providers. Each rule applies to records on the same host, unless otherwise specified. * A CNAME record conflicts with any other record on the same host, and any existing records conflict with a CNAME. Kowalik, et al. Expires 7 December 2026 [Page 55] Internet-Draft Domain Connect June 2026 * An NS record conflicts with all other records on the same host, and with any record whose host is subordinate to the NS host. For example, an NS record for "foo" conflicts with any record at "foo", "www.foo", "bar.foo", etc. Conversely, any other record type conflicts with NS records in the same manner. * MX and SRV records conflict with any other record of the same type on the same host. * A and AAAA records conflict with any other A or AAAA record on the same host, to avoid IPv4 and IPv6 addresses pointing to different services. * TXT record conflict detection is governed by the "txtConflictMatchingMode" property of the template record: - "None" - the record does not conflict with any other TXT record. This is the default. - "All" - the record conflicts with any other TXT record on the same host. - "Prefix" - the record conflicts with any other TXT record on the same host whose value starts with "txtConflictMatchingPrefix". Note: DNS Provider MUST also check applicability of all generated records to the target DNS zone in its own system. For example it is very common for DNS provider not to allow CNAME records to be at the zone apex. 10.4.1. Conflict Detection Special Handling 10.4.1.1. Multi-Instance This processing only REQUIRED for DNS Providers that maintain applied template state. By default a template is expected to be applied only once to a target "domain" and "host", therefore any consecutive attempt to apply the same template would be treated as an update. For some templates however it is desirable to be able to create multiple instances (for example add second TXT record on the same host as opposed to replacing the current value). A template flag multiInstance (Section 6.1) can be set in order to allow for that. This tells the DNS Provider that the template is expected to be written multiple times and that a re-apply MUST NOT Kowalik, et al. Expires 7 December 2026 [Page 56] Internet-Draft Domain Connect June 2026 remove previous instances with the same "host". Regular conflict detection rules MUST still be processed between instances, therefore such a template MUST be designed so that it does not conflict with itself. 10.4.1.2. Essential Records This processing only REQUIRED for DNS Providers that maintain applied template state. A template record is considered essential when it MUST be present and remain consistent with the applied template for the entire lifetime of the service. The *essential* property of a template record controls this behavior and MUST be set to "Always" (the default) for such records. A DNS Provider that maintains applied template state MUST treat an attempt of removal or modification of such an essential record as a conflict indicator, and MUST require the full template to be removed or abort. Records with "essential=OnApply" MUST be applied when the template is first applied, but MAY be subsequently removed or altered - by the user or through the application of another template - without triggering conflict or removal of the owning template. 10.5. Calculating Conflict Resolution A DNS Provider not maintaining applied template state, applying a template whose records conflict with any existing record in the zone MUST remove all those conflicting records. When a DNS Provider maintains applied template state, applying a template whose records conflict with records written by a previously applied template MUST cause the conflicting prior template to be removed in its entirety, unless a conflicting record is explicitly marked as non essential and eligible for removal. As an example: if template T1 wrote records A and B, and template T2 is applied with records B and C, record B conflicts, and T1 is removed together with all its records before T2 is applied. 10.6. User Authorization of Changes It is ultimately left to the DNS Provider to determine the amount of disclosure and/or conflict detection. Kowalik, et al. Expires 7 December 2026 [Page 57] Internet-Draft Domain Connect June 2026 The DNS Provider MUST inform the user of the service that is about to be enabled when requesting authorization. If the user wishes to review the specifics, the DNS Provider SHOULD make the individual DNS records being set available, in order to allow informed decision before changes are applied. If conflicts are detected - at either the template or record level - the DNS Provider SHOULD present these to the user before authorization is granted. For template instances this means identifying services that would be disabled; for records this means identifying records that would be deleted or overwritten. The DNS Provider MUST allow the user to override a detected conflict and proceed with the template application, or to abort the process. When presenting the authorization request to the user, the DNS Provider SHOULD display the template's "providerName" and "serviceName" fields. When a caller supplies "providerName" or "serviceName" request parameters (permitted only when the template's "sharedProviderName" or "sharedServiceName" flags are set, respectively), the DNS Provider SHOULD use those values to augment the displayed name. It is RECOMMENDED however to also display the original "providerName" and "serviceName" defined in the template. When the template's "warnPhishing" field is "true", the DNS Provider SHOULD display additional warnings prompting the user to verify the source of the request before proceeding, and SHOULD provide a more verbose description of the changes about to be applied. 10.7. Template Application In the Synchronous Flow, after authorization is granted, the DNS Provider applies the template to the DNS zone. In the Asynchronous Flow this happens in later point in time. In this case conflict resolution MUST be calculated again for the actual state of the zone and parameters provided with the apply request. The DNS Provider MUST remove all conflicting templates and records from the target zone. The DNS Provider MUST apply all records of the template in totality as one atomic operation. 10.8. Examples Examples of template processing are in Appendix A. Kowalik, et al. Expires 7 December 2026 [Page 58] Internet-Draft Domain Connect June 2026 11. Security Considerations 11.1. Template Variable Phishing Templates that accept variable parameters introduce a phishing risk. The more static the values in a template record, the more secure the template. When variable values cannot be avoided, a bad actor could craft an apply URL substituting a malicious value - for example, a hijacked IP address - and send it to users as a seemingly legitimate reconfiguration request. The user would be presented with a DNS Provider consent screen that appears valid, but would result in DNS being pointed at infrastructure under the attacker's control. Not all templates are susceptible; the risk is proportional to how much of a record's content is controlled by variables. Three mitigations are available to template authors and Service Providers: digitally signing apply requests (see the Section <
>), using an alternative flow not prone to this risk and disabling the synchronous flow via "syncBlock", and setting the "warnPhishing" flag to prompt the DNS Provider to display additional warnings to the user. 12. IANA Considerations 12.1. Underscore "_domainconnect" DNS Node Name Per [RFC8552], please add the following entry to the "Underscored and Globally Scoped DNS Node Names" registry: +=========+================+================+ | RR Type | _NODE NAME | Reference | +=========+================+================+ | TXT | _domainconnect | This document. | +---------+----------------+----------------+ Table 10: IANA Registration for _domainconnect 12.2. Domain Connect Settings Properties Registry IANA is requested to create a new registry named "Domain Connect Settings Properties" under a new registry group "Domain Connect Protocol". Registration policy: Specification Needed (see [RFC8126]). Each entry in the registry MUST include: Kowalik, et al. Expires 7 December 2026 [Page 59] Internet-Draft Domain Connect June 2026 * *Property name*: the JSON key as it appears in the settings response. * *Status*: the lifecycle state of the registration. The following values are defined; IANA MAY define additional values as needed: - "Active": the property is currently in use and its definition is normative. - "Deprecated": the property SHOULD NOT be used in new implementations; it MAY appear in existing deployments for backwards compatibility. - "Reserved": the property appears in earlier versions of the Domain Connect specification (see [DC-SPEC]) and is reserved for back-compatibility. It MUST NOT be redefined in a manner incompatible with [DC-SPEC]. See Section 3, Paragraph 13. * *Kind*: the nature of the defining document. The value MUST be one of: "IETF Standard" for properties defined in a standards- track RFC, "Informational" for properties defined in an Informational RFC, or "Other" for any other specification. * *Reference*: the document that defines the property. The following properties from this specification constitute the initial contents of the registry: Kowalik, et al. Expires 7 December 2026 [Page 60] Internet-Draft Domain Connect June 2026 +=======================+==========+===============+===============+ | *Property Name* | *Status* | *Kind* | *Reference* | +=======================+==========+===============+===============+ | "providerId" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "providerName" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "providerDisplayName" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "urlSyncUX" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "urlAsyncUX" | Reserved | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "urlAPI" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "width" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "height" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "urlControlPanel" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ | "nameServers" | Active | IETF Standard | This document | +-----------------------+----------+---------------+---------------+ Table 11: Initial Domain Connect Settings Properties Implementation Status This section is to be removed before publishing as an RFC. DNS Providers Open Source * Server library (Python):https://github.com/Domain-Connect/ DomainConnectApplyZone Proprietary implementations * ~20 providers, incl. GoDaddy, IONOS, Cloudflare, Squarespace Domains (former Google), Wordpress.com or Plesk * 35% of the .com zone (May'24) Service Providers Open Source Kowalik, et al. Expires 7 December 2026 [Page 61] Internet-Draft Domain Connect June 2026 * Example service: https://exampleservice.domainconnect.org/https://github.com/ Domain-Connect/exampleservice * Client library (Python):https://github.com/Domain-Connect/ domainconnect_python Proprietary implementations * 492 templates from over 250 providers, incl. O365, Google Workspace, Apple Cloud+, Weebly, Squarespace. Source: https://stats.domainconnect.org/ Acknowledgements The authors wish to thank the following persons for their feedback and suggestions as well as for the previous work on the standard: * Roger Carney of GoDaddy Inc. * Chris Ambler of GoDaddy Inc. * Darrel Miller * Peter Thomassen * Paul Hoffmann * Arnt Gulbrandsen Change History This section is to be removed before publishing as an RFC. Change from draft-ietf-dconn-domainconnect-01 to -02 * Removed the Asynchronous OAuth Flow from this document; the synchronous flow is now the sole protocol flow defined here. The asynchronous flow is reserved for a companion extension specification. Change from draft-ietf-dconn-domainconnect-00 to -01 Kowalik, et al. Expires 7 December 2026 [Page 62] Internet-Draft Domain Connect June 2026 * Added comprehensive ABNF grammar to the Terminology section covering all protocol identifiers, domain name forms (including IDN), template fields, OAuth parameters, and signing artifacts; replaced informal prose constraints throughout parameter tables and field definitions with normative ABNF references. * Restructured Template Application: added Group Filtering, Essential Records, Steps to Apply a Template, and focused Conflict Detection, User Authorization of Changes subsections; moved UX and runtime-processing rules into their appropriate sections; moved Domain Connect Objects and Templates before Applying Domain Connect in the document structure. * Restructured request signing into Signing Procedure, Signature Verification, and Public Key Publication * Replaced Sync Apply Interaction with a normative Request/Response/ Error structure; rewrote Verification of Changes as normative text. * Restructured Security Considerations: moved phishing threat into new Template Variable Phishing subsection; editorial cleanup. * Defined extensibility model for DNS Provider Discovery settings response and added IANA "Domain Connect Settings Properties" registry. * Removed non-normative sections (Public Template Repository, General Considerations, Extensions/Exclusions); replaced all occurrences of "browser" with "user agent". * Shortened Trust Model section. Change from draft-kowalik-domainconnect-02 to draft-ietf-dconn- domainconnect-00 * DCONN WG adoption. No other changes. Change from -01 to -02 * Draft refresh from expire. No content changes. Change from -00 to -01 * Changed term Root Domain to Zone Apex to align with [RFC8499]. * Removed example provider names from Service Providers and DNS Providers terminology Kowalik, et al. Expires 7 December 2026 [Page 63] Internet-Draft Domain Connect June 2026 * Added Use Cases * Added Trust Model * Added sequence diagrams for synchronous and asynchronous flows instead of UX mocks * Reviewed use of normative language * Cleaned up usage of terminology * Variable substitution description updated * All URLs are now normatively defined with URI templates Change from draft-kowalik-regext-domainconnect-00 to draft-kowalik- domainconnect-00 * Added possibility to specify any DNS record type in a generic manner. * Added possibility to define variables for numeric fields. * Added IANA registration for _domainconnect record as per [RFC8552] Change from draft-carney-regext-domainconnect-03 to draft-kowalik- regext-domainconnect-00 * Version synchronized with 2.2 version rev. 66 of the public Domain Connect specification. Change from -02 to -03 * Added width/height JSON values returned by DNS Provider Discovery. * Corrected text of GET method for getting the authorization token. * Added clarifying text to Group ID description parameter of the apply template POST method. Quite a few minor edits and clarifications that were found during implementation, especially in the Implementation Considerations section. Change from -01 to -02 * Added new GET method for Service Providers to determine if the DNS Provider supports a specific template. Some other minor edits for clarification. Kowalik, et al. Expires 7 December 2026 [Page 64] Internet-Draft Domain Connect June 2026 Change from draft-carney-regext-domainconnect-00 to -01 * Minor edits and clarifications found during implementation. Normative References [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, DOI 10.17487/RFC1035, BCP 13, RFC 1035, November 1987, . [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", IETF, DOI 10.17487/RFC2782, RFC 2782, February 2000, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", IETF, DOI 10.17487/RFC2119, BCP 14, RFC 2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", IETF, DOI 10.17487/RFC8174, BCP 14, RFC 8174, May 2017, . [RFC7208] Kitterman, S., "Sender Policy Framework (SPF) for Authorizing Use of Domains in Email, Version 1", IETF, DOI 10.17487/RFC7208, RFC 7208, April 2014, . [RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", IETF, DOI 10.17487/RFC6749, RFC 6749, October 2012, . [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record (RR) Types", IETF, DOI 10.17487/RFC3597, RFC 3597, September 2003, . [RFC8259] Bray, T., "The JavaScript Object Notation (JSON) Data Interchange Format", IETF, STD 90, DOI 10.17487/RFC8259, BCP 90, RFC 8259, December 2017, . [RFC8552] Crocker, D., "Scoped Interpretation of DNS Resource Records through "Underscored" Naming of Attribute Leaves", IETF, DOI 10.17487/RFC8552, BCP 222, RFC 8552, March 2019, . Kowalik, et al. Expires 7 December 2026 [Page 65] Internet-Draft Domain Connect June 2026 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", IETF, STD 66, DOI 10.17487/RFC3986, BCP 66, RFC 3986, January 2005, . [RFC7518] Jones, M., "JSON Web Algorithms (JWA)", IETF, DOI 10.17487/RFC7518, RFC 7518, May 2015, . [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cheshire, "Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry", IETF, DOI 10.17487/RFC6335, BCP 165, RFC 6335, August 2011, . [RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M., and D. Orchard, "URI Template", IETF, DOI 10.17487/RFC6570, RFC 6570, March 2012, . [RFC5234] Overell, P. and D. Crocker, "Augmented BNF for Syntax Specifications: ABNF", IETF, STD 68, DOI 10.17487/RFC5234, BCP 68, RFC 5234, January 2008, . [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", IETF, DOI 10.17487/RFC4648, RFC 4648, October 2006, . [RFC5891] Klensin, J., "Internationalized Domain Names in Applications (IDNA): Protocol", IETF, DOI 10.17487/RFC5891, RFC 5891, August 2010, . [RFC5890] Klensin, J., "Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework", IETF, DOI 10.17487/RFC5890, RFC 5890, August 2010, . [RFC9839] Bray, T. and P. Hoffman, "Unicode Character Repertoire Subsets", IETF, DOI 10.17487/RFC9839, RFC 9839, August 2025, . [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", IETF, DOI 10.17487/RFC8126, BCP 26, RFC 8126, June 2017, . Kowalik, et al. Expires 7 December 2026 [Page 66] Internet-Draft Domain Connect June 2026 [RFC9499] Hoffman, P. and K. Fujiwara, "DNS Terminology", IETF, DOI 10.17487/RFC9499, BCP 219, RFC 9499, March 2024, . Informative References [RFC9364] Hoffman, P., "DNS Security Extensions (DNSSEC)", IETF, DOI 10.17487/RFC9364, BCP 237, RFC 9364, February 2023, . [RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS Terminology", IETF, DOI 10.17487/RFC8499, RFC 8499, January 2019, . [DC-SPEC] Blinn, A., Kerola, S., and P. Kowalik, "Domain Connect Specification, Version 2.3 Rev. 67", 2 March 2025, . Appendix A. Examples A.1. Example Template EXAMPLE: Full template example Kowalik, et al. Expires 7 December 2026 [Page 67] Internet-Draft Domain Connect June 2026 { "providerId": "example.com", "providerName": "Example Web Hosting", "serviceId": "hosting", "serviceName": "Wordpress by example.com", "version": 1, "logoUrl": "https://www.example.com/images/billthecat.jpg", "description": "This connects your domain to our web hosting", "records": [ { "type": "A", "groupId": "service", "host": "www", "pointsTo": "%var1%", "ttl": 600 }, { "type": "A", "groupId": "service", "host": "m", "pointsTo": "%var2%", "ttl": 600 }, { "type": "CNAME", "groupId": "service", "host": "webmail", "pointsTo": "%var3%", "ttl": 600 }, { "type": "TXT", "groupId": "verification", "host": "example", "ttl": 600, "data": "%var4%" } ] } A.2. Example Records: Single static host record Consider a template for setting a single host record. The records section of the template would have a single record of type "A" and could have a value of: EXAMPLE: Single static host record example Kowalik, et al. Expires 7 December 2026 [Page 68] Internet-Draft Domain Connect June 2026 [{ "type": "A", "host": "www", "pointsTo": "192.0.2.1", "ttl": 600 }] This would have no variable substitution and the application of this template to a domain would simply set the host name "www" to the IP address "192.0.2.1" A.3. Example Records: Single variable host record for A In the case of a template for setting a single host record from a variable, the template would have a single record of type "A" and could have a value of: EXAMPLE: Single variable host record for A example [{ "type": "A", "host": "@", "pointsTo": "198.51.100.%srv%", "ttl": 600 }] A query string with a key/value pair of srv=2 would cause the application of this template to a domain to set the host name for the apex A record to the IP address "198.51.100.2" with a TTL of 600 A.4. Example Records: Unspecified record type CAA This example shows how to include a set of unspecified record types on an example of CAA records: EXAMPLE: Unspecified record type CAA example Kowalik, et al. Expires 7 December 2026 [Page 69] Internet-Draft Domain Connect June 2026 [ { "type": "CAA", "host": "@", "data": "0 issue \"ca1.example.net\"", "ttl": 1800 }, { "type": "CAA", "host": "@", "data": "0 issuewild \"ca2.example.\"", "ttl": 1800 } ] This would have no variable substitution and the application of this template to a domain would add 2 CAA records. A.5. Example: Template application to DNS Zone and Conflict Resolution Consider a DNS Zone before a template application: $ORIGIN example.com. @ 3600 IN SOA ns11.example.net. support.example.net. 2017050817 7200 1800 1209600 3600 @ 3600 IN NS ns11.example.net. @ 3600 IN NS ns12.example.net. @ 3600 IN A 192.0.2.1 @ 3600 IN A 192.0.2.2 @ 3600 IN AAAA 2001:db8:1234:0000:0000:0000:0000:0000 @ 3600 IN AAAA 2001:db8:1234:0000:0000:0000:0000:0001 @ 3600 IN MX 10 mx1.example.net. @ 3600 IN MX 10 mx2.example.net. @ 3600 IN TXT "v=spf1 a include:spf.example.org ~all" www 3600 IN CNAME other.host.example. Now application of the following template: Kowalik, et al. Expires 7 December 2026 [Page 70] Internet-Draft Domain Connect June 2026 [ { "type":"A", "host":"@", "pointsTo":"203.0.113.2", "ttl":"1800" }, { "type":"A", "host":"www", "pointsTo":"203.0.113.2", "ttl":"1800" }, { "type":"SPFM", "host":"@", "spfRules":"a include:spf.hoster.example" } ] The following DNS Zone would be generated after the template is applied. A following list of conflicts would be detected in this case: @ 3600 IN A 192.0.2.1 @ 3600 IN A 192.0.2.2 @ 3600 IN AAAA 2001:db8:1234:0000:0000:0000:0000:0000 @ 3600 IN AAAA 2001:db8:1234:0000:0000:0000:0000:0001 After changes applied the zone would be updated to the following state. Note existing A and AAAA records removed due to the conflicts as well as SPF TXT record content merged with the existing entry. $ORIGIN example.com. @ 3600 IN SOA ns11.example.net. support.example.net. 2017050920 7200 1800 1209600 3600 @ 3600 IN NS ns11.example.net. @ 3600 IN NS ns12.example.net. @ 1800 IN A 203.0.113.2 @ 3600 IN MX 10 mx1.example.net. @ 3600 IN MX 10 mx2.example.net. @ 1800 IN TXT "v=spf1 a include:spf.example.org include:spf.hoster.ex ample ~all" www 1800 IN A 203.0.113.2 Kowalik, et al. Expires 7 December 2026 [Page 71] Internet-Draft Domain Connect June 2026 A.6. Example: SPF Record Merging Consider a DNS Zone before a template application: $ORIGIN example.com. @ 3600 IN SOA ns11.example.net. support.example.net. 2017050817 7200 1800 1209600 3600 @ 3600 IN NS ns11.example.net. @ 3600 IN NS ns12.example.net. Now application of the following template of Mail service: [ { "type":"MX", "host":"@", "priority": "10", "pointsTo":"mx1.example.net", "ttl":"1800" }, { "type":"MX", "host":"www", "priority": "10", "pointsTo":"mx2.example.net", "ttl":"1800" }, { "type":"SPFM", "host":"@", "spfRules":"a include:spf.example.net" } ] Expected result in the DNS Zone $ORIGIN example.com. @ 3600 IN SOA ns11.example.net. support.example.net. 2017050817 7200 1800 1209600 3600 @ 3600 IN NS ns11.example.net. @ 3600 IN NS ns12.example.net. @ 3600 IN MX 10 mx1.example.net. @ 3600 IN MX 10 mx2.example.net. @ 3600 IN TXT "v=spf1 a include:spf.example.net ~all" Kowalik, et al. Expires 7 December 2026 [Page 72] Internet-Draft Domain Connect June 2026 In the next step application of the following template of Newsletter service: [ { "type":"SPFM", "host":"@", "spfRules":"include:_spf.newsletter.example" } ] Expected result in the DNS Zone. Note merged SPF entry. $ORIGIN example.com. @ 3600 IN SOA ns11.example.net. support.example.net. 2017050817 7200 1800 1209600 3600 @ 3600 IN NS ns11.example.net. @ 3600 IN NS ns12.example.net. @ 3600 IN MX 10 mx1.example.net. @ 3600 IN MX 10 mx2.example.net. @ 3600 IN TXT "v=spf1 a include:spf.example.net include:_spf.newslett er. example ~all" Authors' Addresses P Kowalik DENIC eG Theodor-Stern-Kai 1 Frankfurt am Main Germany Email: pawel.kowalik@denic.de URI: https://denic.de A Blinn Email: arnold@arnoldblinn.com J Kolker GoDaddy Inc. 14455 N. Hayden Rd. #219 Scottsdale, United States of America Email: jkolker@godaddy.com URI: https://www.godaddy.com Kowalik, et al. Expires 7 December 2026 [Page 73] Internet-Draft Domain Connect June 2026 S Kerola Cloudflare, Inc. 101 Townsend St San Francisco, United States of America Email: kerolasa@cloudflare.com URI: https://cloudflare.com Kowalik, et al. Expires 7 December 2026 [Page 74]