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Versions: 00 01 02 03 05                                                
Network Working Group                                          C. Newman
Internet Draft: Originator Info Message Header                  Innosoft
Document: draft-newman-msgheader-originfo-02.txt             August 1997


                     Originator-Info Message 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 view the entire list of current Internet-Drafts, please check
     the "1id-abstracts.txt" listing contained in the Internet-Drafts
     Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net
     (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East
     Coast), or ftp.isi.edu (US West Coast).


Introduction

     This proposal is an attempt to provide a standard header to
     indicate information about the message originator without implying
     that there is a deliverable mailbox or mandating that internal
     network information be revealed.  The "Originator-Info" header is
     intended to make the "X-Sender" and "X-X-Sender" headers obsolete.

     Many mail clients on personal computers are now using a
     non-standard "X-Sender" header to identify the originator of a
     message without the implication that the sender has a known
     deliverable mailbox (unlike the "Sender" header).  Usually this
     "X-Sender" header is constructed from the credentials used to login
     to a POP [POP3], IMAP [IMAP4], or NNTP [NNTP] server.  Such
     credentials often do not refer to a deliverable mailbox, and
     therefore MUST NOT be used to construct a return or reply address.

     Unfortunately, some mailing list systems now use the "X-Sender"
     header for authorization reply, or return messages.  This causes
     misdelivery for systems where the login credentials do not refer to



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Internet Draft       Originator-Info Message Header          August 1997


     a deliverable mailbox and leaves some users unable to unsubscribe
     to certain mailing lists.  Some clients have responded to this
     problem by supporting an "X-X-Sender" header.  This situation is
     obviously problematic.


1. Conventions Used in this Document

     The key words "REQUIRED", "MUST", "MUST NOT", "SHOULD", "SHOULD
     NOT", and "MAY" in this document are to be interpreted as described
     in "Key words for use in RFCs to Indicate Requirement Levels"
     [KEYWORDS].


2. Originator-Info header

     The Originator-Info header provides a list of attributes which may
     be used to trace the originator of an Internet message [IMAIL].
     These attributes do not in any way imply the existence of a
     deliverable mailbox and MUST NOT be used for authorization or to
     construct a reply or return address.

     Example:

         From: Chris Newman <chris.newman@innosoft.com>
         Originator-Info: login-token=avsgl; server=cyrus.andrew.cmu.edu

     This example indicates that a person whose identity can be
     determined from the token "avsgl" was logged into the server
     "cyrus.andrew.cmu.edu" when this message was composed.

     An "Originator-Info" header SHOULD be generated by Internet mail
     user agents (MUA) upon submission of an Internet message [IMAIL] to
     a delivery system if the MUA is unable to verify the existence of a
     deliverable mailbox for the current user and is authenticated to an
     Internet service such as POP or IMAP.

     Multiple messages from a given user MAY have different
     Originator-Info headers, as that user may have access to multiple
     servers and/or login identities.  In addition, mail servers are
     renamed more frequently than email addresses change.  For these
     reasons, Originator-Info MUST NOT be used for any purpose other
     than tracing the originator of the message.  Specifically,
     Originator-Info MUST NOT be used to control access to mail based
     services, although such services MAY record Originator-Info in log
     files.





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Internet Draft       Originator-Info Message Header          August 1997


2.1. "login-token" attribute

     The login-token attribute is used to allow the identity of the
     sender to be traced without explicitly revealing that identity.  It
     contains site-specific information which may be used to recover the
     login-id (see section 2.2) of the originator.  For example, it
     might be constructed with an MD5 hash [MD5] of the login-id and a
     site-specific secret.  The login-token MAY use an algorithm which
     produces a different token for each message.  An Originator-Info
     header SHOULD include a login-token attribute.


2.2. "login-id" attribute

     The login-id attribute indicates the login identifier that was used
     in a POP "USER" [POP3] or "AUTH" [POP3-AUTH] command or an IMAP
     "LOGIN" or "AUTHENTICATE" [IMAP4] command.  The login-id may also
     be obtained from other services such as a Kerberos authentication
     library.  An Originator-Info header MAY include a login-id
     attribute instead of a login-token attribute.  A program
     interpreting this header MUST NOT form an email address from the
     "login-id" and "server" attributes.  Such an address may not be
     deliverable.

     Example:

         From: Chris Newman <chris.newman@innosoft.com>
         Originator-Info: login-id=nifty; server=cyrus.andrew.cmu.edu


2.3. "server" attribute

     The server attribute is a fully qualified Internet domain name
     [DOM-NAME] of a mail server or other Internet server which the user
     was authenticated to when the message was submitted. An
     Originator-Info header SHOULD include a server attribute.


2.4. "token-authority" attribute

     This attribute contains a human readable string providing
     information about the individual or service that is capable of
     translating the login-token.  When absent, postmaster@<server> can
     be assumed, where <server> is the value of the server attribute.

     Examples:

         Originator-Info: login-token=avsgl; server=cyrus.andrew.cmu.edu;



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Internet Draft       Originator-Info Message Header          August 1997


                    token-authority="nifty@cyrus.andrew.cmu.edu"

         Originator-Info: login-token=avsgl; server=cyrus.andrew.cmu.edu;
                    token-authority="Don't you recognize ROT13?"

         Originator-Info: login-token=avsgl; server=cyrus.andrew.cmu.edu;
                    token-authority="phone 555-555-5555, ask for Mr. Spook"


2.5. Other attributes

     Other attributes MAY be used to provide additional information.
     There is no requirement to register attributes as the
     Originator-Info header is not intended for automated processing.
     For example, an MUA on a Macintosh may wish to include the owner
     name as set in the "Sharing Setup" control panel.

     Example:

         From: Chris Newman <chris.newman@innosoft.com>
         Originator-Info: login-id=nifty; server=cyrus.andrew.cmu.edu;
                          MacOS-owner-name=nifty


3. ABNF for Originator-Info header

     This defines the formal syntax for the "Originator-Info" header
     using the ABNF notation defined in RFC 822 [RFC-822] and using
     terminals defined in MIME [MIME-IMB].

     originator-info := "Originator-Info:" parameter *(";" parameter)

4. Security Considerations

     The "Originator-Info" header is useful for tracing the source of
     Internet messages.  However, it contains no authenticated
     information and is completely susceptible to spoofing by an
     intelligent sender or intervening host.  Therefore it is not a
     substitute secure message systems such as PGP-MIME [PGP-MIME].

     Some sites have concerns about revealing the names of internal
     servers and login identities.  MUAs could accommodate such sites
     with an option to use the domain name of a SOCKS [SOCKS5] server
     (or other firewall) in the "server" attribute instead of a private
     mail server.  Sites with no such considerations MAY use "login-id"
     instead of "login-token".





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Internet Draft       Originator-Info Message Header          August 1997


5. Multinational Considerations

     Parameters in character sets other than US-ASCII MAY use MIME
     parameter extensions [MIME-PARAM].  This MAY also be used to
     provide language labeling and continuations.


6. References

     [DOM-NAME] Mockapetris, P., "Domain Names - Implementation and
     Specification", RFC 1035, ISI, November 1987.

          <ftp://ds.internic.net/rfc/rfc1035.txt>

     [IMAIL] Crocker, D., "Standard for the Format of Arpa Internet Text
     Messages", RFC 822, University of Delaware, August 1982.

          <ftp://ds.internic.net/rfc/rfc822.txt>

     [IMAP4] Crispin, M., "Internet Message Access Protocol - Version
     4", RFC 1730, University of Washington, December 1994.

             <ftp://ds.internic.net/rfc/rfc1730.txt>

     [KEYWORDS] Bradner, "Key words for use in RFCs to Indicate
     Requirement Levels", RFC 2119, Harvard University, March 1997.

         <ftp://ds.internic.net/rfc/rfc2119.txt>

     [MD5]  Rivest, R. "The MD5 Message Digest Algorithm", RFC 1321, MIT
     Laboratory for Computer Science, April 1992.

          <ftp://ds.internic.net/rfc/rfc1321.txt>

     [MIME-IMB] Freed, Borenstein, "Mulitpurpose Internet Mail
     Extensions (MIME) Part One: Format of Internet Message Bodies", RFC
     2045, Innosoft, First Virtual, November 1996.

             <ftp://ds.internic.net/rfc/rfc2045.txt>

     [MIME-PARAM] Freed, Moore, "MIME Parameter Value and Encoded Word
     Extensions: Character Sets, Languages, and Continuations", RFC
     XXXX, Innosoft, University of Tennessee, March 1997.








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Internet Draft       Originator-Info Message Header          August 1997


     [NNTP] Kantor, Lapsley, "Network News Transfer Protocol: A Proposed
     Standard for the Stream-Based Transmission of News", RFC 977, U.C.
     San Diego, U.C. Berkeley, February 1986.

             <ftp://ds.internic.net/rfc/rfc977.txt>

     [PGP-MIME] Elkins, M., "MIME Security with Pretty Good Privacy
     (PGP)", RFC 2015, The Aerospace Corporation, October 1996.

          <ftp://ds.internic.net/rfc/rfc2015.txt>

     [POP3] Myers, J., Rose, M., "Post Office Protocol - Version 3", RFC
     1939, Carnegie Mellon, Dover Beach Consulting, Inc., May 1996.

             <ftp://ds.internic.net/rfc/rfc1939.txt>

     [SOCKS5] Leech, Ganis, Lee, Kuris, Koblas, Jones, "SOCKS Protocol
     Version 5", RFC 1928, Bell-Northern Research Ltd, International
     Business Machines, NEC Systems Laboratory, Unify Corporation,
     Hewlett-Packard Company, March 1996.

          <ftp://ds.internic.net/rfc/rfc1928.txt>


7. Author's Address

     Chris Newman
     Innosoft International, Inc.
     1050 Lakes Drive
     West Covina, CA 91790 USA

     Email: chris.newman@innosoft.com



















Newman                                                          [Page 6]