HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 10:41:50 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Tue, 17 Mar 1998 16:30:00 GMT ETag: "361d60-1300-350ea508" Accept-Ranges: bytes Content-Length: 4864 Connection: close Content-Type: text/plain Network Working Group Jacob Palme Internet Draft Stockholm University/KTH Sweden Category-to-be: Experimental standard July 1997 Expires January 1998 Loop control for the Auto-Submitted e-mail header Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind, since this document is mainly a compilation of information taken from other RFC-s.. Distribution of this memo is unlimited. Abstract This memo introduces certain advanced features for the Auto-Submitted e-mail header. Changes from the previous version of this IETF draft The specification of the Auto-Submitted header itself has been moved to draft-ietf-mailext-new-fields-08-txt. However, the controversial loop control feature has been removed from that document, and is instead specified here. The intention is that Auto-Submitted without loop control is to become a proposed standard, while the loop-control feature is to become an experimental standard. 1. Introduction This memo introduces loop control features for the Auto- Submitted header defined in [8]. 2. New syntax for the Auto-Submitted header Syntax: auto-submitted-field = "Auto-Submitted ":" auto- submitted auto-submitted = ( "no" / "auto-generated" / "auto-replied" / "inter-application" / "x-" / " ) = *( ";" ) = "loopstep: / = *DIGIT The added syntax as compared to [8] is the new value "inter-application" and the new parameter "loopstep:" followed by a positive number. These are used in the following ways: inter-application is used when it is known that both the sender and the recipient of this message is an automatic process. When an Auto-Submitted message is sent in response to another Auto-Submitted message, the value of loopstep is increased by 1. A message without any loopstep parameter is assumed to have "loopstep: 1". The value of loopstep can be used to stop loops by not producing automatic responses to messages if loopstep has a value above a certain limit. The size of this limit is application- dependent. 3. Security considerations This proposal raises no new security concerns, instead, it reduces the risk to security of certain kinds of loops. 4. Acknowledgments Keith Moore and Uzi Paz have influenced this document with valuable suggestions. 5. References [1] D. Crocker: "Standard for the format of ARPA Internet text messages." STD 11, RFC 822, August 1982. [2] S. Hardcastle-Kille: "Mapping between X.400(1988) / ISO 10021 and RFC 822", RFC 1327 May 1992. [3] ISO/ITU: "Message Handling Systems", ISO international standard 10021, ITU recommendation X.400. [4] ISO/ITU: "Message Handling Systems, Part 7: Interpersonal Messaging System, ISO international standard 10021-7, ITU recommendation X.420. [5] N. Borenstein, N. Freed: "MIME (Multipurpose Internet Mail Extensions)", RFC 1521, September 1993. [6] K. Moore, G. Vaudreuil, "An Extensible Message Format for Delivery Status Notifications", RFC 1894, January 1996. [7] K. Moore, "SMTP Service Extension for Delivery Status Notifications", RFC 1891, January 1996. [8] J. Palme, "The Auto-Submitted, Supersedes and Expires E-mail Headers. drafti-ietf-mailext-new-fields-08.txt. July 1997. 6. Author's address Jacob Palme Phone: +46-8-16 16 67 Stockholm University/KTH Fax: +46-8-783 08 29 Electrum 230 E-mail: jpalme@dsv.su.se S-164 40 Kista, Sweden