One document matched: draft-ietf-mailext-new-fields-00.txt

                 Additional RFC 822 heading attributes

1. Status of this Memo

  This document is an Internet-Draft.  Internet-Drafts are working
  documents of the Internet Engineering Task Force (IETF), its
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  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.

2. Abstract

  This memo introduces three new e-mail (RFC 822) heading fields, 
  obsoletes, auto-submitted and expires. 

3. Introduction

  This memo introduces certain heading attributes for Internet e-mail 
  (RFC 822) headers which will enhance the e-mail service in various 
  ways.

  The heading attributes introduced are: Obsoletes, Auto-Submitted and 
  Expires.

4. Relation to X.400 gatewaying recommendation

  Some of the attributes defined in this document are also defined in 
  recommendations for gatewaying [2] between X.400 [3] and Internet 
  mail. However, those recommendations are only valid for gateways. By 
  repeating the attributes here, such attributes are recommended for 
  general Internet e-mail usage. This document also gives fuller 
  descriptions of such attributes than is given by X.400 gatewaying 
  recommendations.


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Internet draft     Additional RFC 822 heading attributes      March 1995


5. Obsoletes

  Syntax: obsoletes-field = "Obsoletes" ":" 1#msg-id

  The message identifiers (msg-id) use the msg-id format, as defined in 
  RFC 822 [1].

  This field identifies previous correspondence, which this message 
  obsoletes. A user agent is expected to handle this field in much the 
  same way as the In-Reply-To and References heading field.

  (a) Thus, this field does not imply any mandatory deletion of the 
      previous correspondence.

  (b) User agents which provide user commands for getting from a reply 
      to the replied-to message (or for getting from a replied-to 
      message to its replies), may provide similar commands for getting 
      from an obsoleting message to the obsoleted message (or for 
      getting from an obsoleted message to its revised version).

  (c) User agents may normally show the recipient both the previous and 
      the obsoleting message. If, however, both the previous and the 
      obsoleting message have arrived, both having the same author, but 
      the user has not yet seen either of them, a user agent may show 
      only the obsoleting message, but also show the obsoletes-field to 
      inform the recipient that this message obsoletes a previous 
      message.

  (d) User agents might issue a warning if an obsoleting message arrives 
      with a different author than the author of the obsoleted message.
  
  Note 1: A heading attribute with similar functionality which sometimes 
  is seen is "Supersedes:". However, "Obsoletes:" is preferred to 
  "Supersedes:". Safe software should understand both "Obsoletes:" and 
  "Supersedes:" but should generate "Obsoletes:".

  Note 2: A similar attribute is defined in X.420 [4].

6. Auto-Submitted

  Syntax: auto-submitted-field = "Auto-Submitted" ":" auto-submitted

          auto-submitted = "no" / "auto-generated" / "auto-replied" /
                           "auto-forwarded"

  This attribute indicates whether the message was sent with or without 
  explicit human control. This attribute, with the value "auto-replied" 
  should be used for example for messages sent by mail servers and 
  vacation servers in reply to incoming messages. Mail servers and 
  vaction servers should not reply to auto-replied messages sent to 
  them, in order to avoid loops.

  "no" indicates that this message was sent with explicit human action. 


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Internet draft     Additional RFC 822 heading attributes      March 1995


  The absence of this attribute indicates that information is not 
  available as to whether this message was sent with or without explicit 
  human control.

  This means that also other means of prevention of loops is necessary, 
  such as making the SMTP-sender null for messages from mail servers and 
  vacation servers. This will be handled more fully in separate 
  recommendations for mail servers and vacation servers.

  Note 1: A similar attribute is defined in X.420 [4].

7. Expiry-date:

  Syntax: Expiry-date-field = "Expires" ":" date-time

  The expiry-date field indicates a date-time, at which this message 
  expires. The field can be used both to limit and to extend the life of 
  a message. User agents and servers which employ automatic purging of 
  old messages may let this attribute influence the purging process.
  
  Note 1: This attribute is also defined, with similar meaning, in 
  Usenet News [5] and in X.420 [4].
  
  Note 2: Unfortunately, RFC 1327 [2] specifies this field as "Expiry-
  date" while Usenet News [5] specifies it as "Expires". Safe e-mail 
  software should accept both variants, but generate the "Expires" 
  variant.
  
8. 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]  M.R. Horton, R. Adams: "Standard for interchange of USENET
       messages", RFC 1036, December 1987.

9. Author's address

  Jacob Palme                          Phone: +46-8-16 16 67
  Stockholm University/KTH             Fax: +46-8-703 90 25 (not fast)
  Electrum 230                         E-mail: jpalme@dsv.su.se
  S-164 40 Kista, Sweden



Palme                Expires September 1995                    [Page 1]