XEP-0157: Contact Addresses for XMPP Services

Abstract:This document defines a method for specifying contact addresses related to an XMPP service.
Authors:Peter Saint-Andre, Jacek Konieczny
Copyright:© 1999 – 2017 XMPP Standards Foundation. SEE LEGAL NOTICES.
Last Updated:2018-07-21

NOTICE: This Informational specification defines a best practice or protocol profile that has been approved by the XMPP Council and/or the XSF Board of Directors. Implementations are encouraged and the best practice or protocol profile is appropriate for deployment in production systems.

Table of Contents

1. Introduction
2. Email Address
3. XMPP Addresses
4. Deployment Notes
5. Security Considerations
6. IANA Considerations
7. XMPP Registrar Considerations
    7.1. Field Standardization

    A: Document Information
    B: Author Information
    C: Legal Notices
    D: Relation to XMPP
    E: Discussion Venue
    F: Requirements Conformance
    G: Notes
    H: Revision History

1. Introduction

RFC 2142 [1] specifies conventional electronic mailbox names for common services, roles, and functions related to SMTP, NNTP, and HTTP (such as hostmaster@domain.tld, usenet@domain.tld, and abuse@domain.tld). However, no such conventional email address or XMPP address has been specified for XMPP services (e.g., in RFC 3920 [2]). This document remedies that oversight, and the email recommendation specified here has been incorporated into RFC 6120 [3].

2. Email Address

Consistent with RFC 2142, a domain that offers a Jabber/XMPP service SHOULD provide an Internet mailbox of "XMPP" for inquiries related to that service.

3. XMPP Addresses

The administrators of an XMPP service may desire to advertise contact information related to that service. [4] This contact information may include email addresses, web URLs, and JabberIDs for specific roles and functions such as the service administrators, abuse reports, customer feedback, sales inquiries, technical support, and security concerns. For this purpose, domains SHOULD support the electronic mailboxes required by RFC 2142. However, additional contact mechanisms may be desirable, and it would be helpful if those who want to initiate contact could discover the contact information using standard XMPP extensions, specifically Service Discovery (XEP-0030) [6]. To make such discovery possible, we specify a Service Discovery Extensions (XEP-0128) [7] mechanism that a server SHOULD return in response to service discovery information ("disco#info") requests sent to the bare domain of the server. This information MUST be scoped using a FORM_TYPE of "http://jabber.org/network/serverinfo" (as already specified in XEP-0128) and data form fields registered for this purpose as defined in the XMPP Registrar Considerations section of this document.

To illustrate this usage, consider the following example of a disco#info request sent to the mythical shakespeare.lit XMPP server:

Example 1. Entity queries server for information

<iq from='juliet@capulet.com/chamber'
  <query xmlns='http://jabber.org/protocol/disco#info'/>

Example 2. Server communicates information

<iq from='shakespeare.lit'
  <query xmlns='http://jabber.org/protocol/disco#info'>
    <identity category='server' type='im'/>
    <feature var='http://jabber.org/protocol/disco'/>
    <x xmlns='jabber:x:data' type='result'>
      <field var='FORM_TYPE' type='hidden'>
      <field var='abuse-addresses'>
      <field var='admin-addresses'>
      <field var='feedback-addresses'>
      <field var='sales-addresses'>
      <field var='security-addresses'>
      <field var='support-addresses'>

4. Deployment Notes

The "domain.tld" at which the XMPP service is hosted need not be the same as the "domain.tld" at which the email service is hosted. For example, it is common for a service provider to host its XMPP service at a hostname such as "jabber.example.org" whereas email related to the service provider is sent to a hostname of "example.org". Thus while the XMPP address and email address may be the same for some service providers (e.g., both "xmpp@example.com"), that similarity is not necessary.

Although some service providers that use the same address for both XMPP and email messaging may integrate delivery of messages sent by those mechanisms (e.g., XMPP messages sent while a user is offline are redirected to email delivery), XMPP and email remain separate messaging systems.

A service provider that supports the functionality specified herein may advertise the service through a Mailto URI (see RFC 2368 [8]) of <mailto:xmpp@domain.tld> and through appropriate XMPP URIs (see RFC 5122 [9]) such as <xmpp:admins@domain.tld> or (per XMPP URI Query Components (XEP-0147) [10]) <xmpp:admins@domain.tld?message>.

It is a matter of service policy whether the XMPP addresses provided are dedicated accounts or aliases that redirect communications to the appropriate accounts.

5. Security Considerations

Providing or advertising contact addresses may open those addresses to unwanted communication. Server administrators should balance the need for openness with the desire for control over communication with customers and peers.

6. IANA Considerations

This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [11].

7. XMPP Registrar Considerations

The XMPP Registrar [12] includes the following information in its registries.

7.1 Field Standardization

Field Standardization for Data Forms (XEP-0068) [13] defines a process for standardizing the fields used within Data Forms qualified by a particular namespace, and XEP-0128 describes how to use field standardization in the context of service discovery. This section registers fields for server information scoped by the "http://jabber.org/network/serverinfo" FORM_TYPE.

Registry Submission

    Forms enabling the communication of contact addresses
    and other server information.
      label='One or more addresses for communication related to abusive traffic'/>
      label='One or more addresses for communication with the service administrators'/>
      label='One or more addresses for customer feedback'/>
      label='One or more addresses for communication related to sales and marketing'/>
      label='One or more addresses for communication related to security concerns'/>
      label='One or more addresses for customer support'/>


Appendix A: Document Information

Series: XEP
Number: 0157
Publisher: XMPP Standards Foundation
Status: Active
Type: Informational
Version: 1.0.1
Last Updated: 2018-07-21
Approving Body: XMPP Council
Dependencies: XMPP Core, XEP-0128
Supersedes: None
Superseded By: None
Short Name: N/A
Source Control: HTML
This document in other formats: XML  PDF

Appendix B: Author Information

Peter Saint-Andre

Email: xsf@stpeter.im
JabberID: peter@jabber.org
URI: http://stpeter.im/

Jacek Konieczny

Email: jajcus@jajcus.net
JabberID: jajcus@jabber.bnet.pl

Appendix C: Legal Notices


This XMPP Extension Protocol is copyright © 1999 – 2018 by the XMPP Standards Foundation (XSF).


Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.

Errata can be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. RFC 2142: Mailbox Names for Common Services, Roles and Functions <http://tools.ietf.org/html/rfc2142>.

2. RFC 3920: Extensible Messaging and Presence Protocol (XMPP): Core <http://tools.ietf.org/html/rfc3920>.

3. RFC 6120: Extensible Messaging and Presence Protocol (XMPP): Core <http://tools.ietf.org/html/rfc6120>.

4. Many existing Jabber/XMPP server implementations use the bare domain <domain.tld> of the server (e.g., "example.org") as an alias for the server administrators, such that a <message/> stanza addressed to that domain name is delivered to the JIDs of the server administrators. (Currently, this functionality does not apply to <iq/> or <presence/> stanzas.) Unfortunately, using the "domain.tld" address as a way to direct messages to the server administrators may result in overloading of the bare domain address (i.e., it may be desirable to send messages to the server's address without having those messages delivered to the server admins, for example if the server doubles as a Publish-Subscribe (XEP-0060) [5] service). Therefore, it is instead RECOMMENDED to support service discovery of contact addresses as specified herein.

5. XEP-0060: Publish-Subscribe <https://xmpp.org/extensions/xep-0060.html>.

6. XEP-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>.

7. XEP-0128: Service Discovery Extensions <https://xmpp.org/extensions/xep-0128.html>.

8. RFC 2368: The mailto URL scheme <http://tools.ietf.org/html/rfc2368>.

9. RFC 5122: Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP) <http://tools.ietf.org/html/rfc5122>.

10. XEP-0147: XMPP URI Query Components <https://xmpp.org/extensions/xep-0147.html>.

11. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.

12. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.

13. XEP-0068: Field Data Standardization for Data Forms <https://xmpp.org/extensions/xep-0068.html>.

Appendix H: Revision History

Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/

Version 1.0.1 (2018-07-21)

Add missing dependency metadata.


Version 1.0 (2007-01-31)

Per a vote of the XMPP Council, advanced specification to Active.


Version 0.6 (2007-01-25)

Per Council feedback, restored service discovery of XMPP contact addresses from version 0.1 of spec.


Version 0.5 (2007-01-06)

Changed XMPP address from domain.tld/admin to xmpp@domain.tld.


Version 0.4 (2007-01-05)

Changed XMPP address from domain.tld to domain.tld/admin to prevent overloading.


Version 0.3 (2006-07-31)

Recommended support for RFC2142-style mailbox in addition to XMPP address.


Version 0.2 (2006-07-18)

Removed extended addressing recommendations pending further review.


Version 0.1 (2005-09-08)

Initial version.


Version 0.0.2 (2005-09-06)

Added security considerations and XMPP Registrar considerations.


Version 0.0.1 (2005-08-27)

First draft.