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A "Null MX" No Service Resource Record for Domains That Accept No Mail (RFC7505) Disclosure Number: IPCOM000242282D
Original Publication Date: 2015-Jun-01
Included in the Prior Art Database: 2015-Jul-01
Document File: 12 page(s) / 13K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Levine: AUTHOR [+1]


This document defines the No Service MX, informally called "null MX", as a simple mechanism by which a domain can indicate that it does not accept email.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 21% of the total text.

Internet Engineering Task Force (IETF)                         J. Levine Request for Comments: 7505                          Taughannock Networks Category: Standards Track                                      M. Delany ISSN: 2070-1721                                               Apple Inc.                                                                June 2015

  A "Null MX" No Service Resource Record for Domains That Accept No Mail


   Internet mail determines the address of a receiving server through    the DNS, first by looking for an MX record and then by looking for an    A/AAAA record as a fallback.  Unfortunately, this means that the    A/AAAA record is taken to be mail server address even when that    address does not accept mail.  The No Service MX RR, informally    called "null MX", formalizes the existing mechanism by which a domain    announces that it accepts no mail, without having to provide a mail    server; this permits significant operational efficiencies.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force    (IETF).  It represents the consensus of the IETF community.  It has    received public review and has been approved for publication by the    Internet Engineering Steering Group (IESG).  Further information on    Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,    and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2015 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    ( in effect on the date of    publication of this document.  Please review these documents    carefully, as they describe your rights and restrictions with respect    to this document.  Code Components extracted from this document must    include Simplified BSD License text as described in Section 4.e of    the Trust Legal Provisions and are provided without warranty as    described in the Simplified BSD License.

Levine & Delany              Standards Track                    [Page 1]
 RFC 7505                         Null MX                       June 2015

 Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2    2.  Conventions Used in This Document . . . . . . . . . . . . . .   2    3.  MX Resource Records Specifying...