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Versions: (draft-gellens-lemonade-mms-mapping) 00 01 02 03 04 05 06 RFC 4356

Internet Draft: Mapping Between MMS and Internet Mail         R. Gellens
Document: draft-ietf-lemonade-mms-mapping-01.txt                Qualcomm
Expires: April 2005                                         October 2004


         Mapping Between the Multimedia Messaging Service (MMS)
                           and Internet Mail


Status of this Memo

    By submitting this Internet-Draft, I certify that any applicable
    patent or other IPR claims of which I am aware have been disclosed
    and any of which I become aware will be disclosed, in accordance
    with RFC 3668 (BCP 79).

    By submitting this Internet-Draft, I accept the provisions of
    Section 3 of RFC 3667 (BCP 78).

    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."

    The list of current Internet-Drafts can be accessed at
    http://www.ietf.org/ietf/1id-abstracts.txt The list of
    Internet-Draft Shadow Directories can be accessed at
    http://www.ietf.org/shadow.html.


Copyright Notice

    Copyright (C) The Internet Society (2004).  All Rights Reserved.


Abstract

    The cellular telephone industry has defined a service known as the
    Multimedia Messaging Service (MMS).  This service uses formats and
    protocols which are similar to, but differ in key ways from those
    used in Internet mail.






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    This document specifies how to exchange messages between these two
    services, including mapping information elements as used in MMS
    X-Mms-* headers as well as delivery and disposition reports, to and
    from that used in ESMTP and Internet message headers.















































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Table of Contents

    1  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
      1.1  Scope   . . . . . . . . . . . . . . . . . . . . . . . . .   3
      1.2  Conventions Used in this Document  . . . . . . . . . . . .  4
      1.3  Definitions . . . . . . . . . . . . . . . . . . . . . . .   4
      1.4  Abbreviations  . . . . . . . . . . . . . . . . . . . . . .  5
      1.5  Assumptions . . . . . . . . . . . . . . . . . . . . . . .   6
    2  Mapping Between MMS and Internet Mail  . . . . . . . . . . . .  6
      2.1  Mapping Specification . . . . . . . . . . . . . . . . . .   6
        2.1.1  MMS to Internet Mail . . . . . . . . . . . . . . . . .  6
        2.1.2  Internet Mail to MMS  . . . . . . . . . . . . . . . .   7
        2.1.3  MMS Information Element Mappings . . . . . . . . . . .  7
          2.1.3.1  Table 1: MM3 Mappings . . . . . . . . . . . . . .   8
          2.1.3.2  Conversion of messages from MMS to Internet format 10
            2.1.3.2.1  Table 2: Importance Mappings (MMS to Internet  14
            2.1.3.2.2  Table 3: X-Priority Mappings (MMS to Internet  14
          2.1.3.3  Conversion of messages from Internet to MMS format 17
            2.1.3.3.1  Table 4: Priority Mappings (Internet Message t 19
        2.1.4  Report Generation and Conversion  . . . . . . . . . .  20
          2.1.4.1  Delivery Report Mapping from MMS to Internet Messa 21
            2.1.4.1.1  Table 5: Delivery Report Mappings (MMS to Inte 21
          2.1.4.2  Delivery Report Mapping from Internet Message to M 23
            2.1.4.2.1  Table 6: Delivery Report Mappings (Internet Me 23
          2.1.4.3  Read Report Mapping from MMS to Internet Message . 24
            2.1.4.3.1  Table 7: Read Report Mappings (MMS to Internet 25
          2.1.4.4  Disposition Report Mapping from Internet Message t 26
            2.1.4.4.1  Table 8: Disposition Report Mappings (Internet 26
        2.1.5  Message Delivery . . . . . . . . . . . . . . . . . . . 27
    3  Security Considerations . . . . . . . . . . . . . . . . . . .  27
    4  Normative References . . . . . . . . . . . . . . . . . . . . . 29
    5  Informative References  . . . . . . . . . . . . . . . . . . .  30
    6  Author's Address . . . . . . . . . . . . . . . . . . . . . . . 31
      Intellectual Property Statement  . . . . . . . . . . . . . . .  31
      Full Copyright Statement  . . . . . . . . . . . . . . . . . . . 32
      Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . .  32


1 Introduction

1.1 Scope

    This document describes how to exchange messages with Internet mail
    systems.  This includes translation between MMS (as defined by
    3GPP/3GPP2/OMA) and Internet Mail messages using Extended Simple
    Mail Transfer Protocol [SMTP] and Internet message format [Msg-Fmt].
    This also includes translation between delivery and disposition
    reports as used in MMS and in Internet mail ([DSN-Msg] and [MDN]).



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    The MMS architecture [Stage_2] and specifications [Stage_3] refer to
    interfaces as reference points named MMx.  For example, MM1 is the
    client-server interface, MM4 is the server-server interface, and MM3
    is an interface to "external" or non-MMS systems.  The specification
    in this document can be used for message exchange between any system
    which uses Internet Message formats and protocols and an MMS system;
    from the perspective of the MMS system, reference point MM3 is used.

    This document includes support for voice messages specified by the
    Voice Profile for Internet Mail [VPIM].  The VPIM specification
    allows voice messages to be exchanged between voice mail systems
    using Internet mail format [Msg-Fmt] and transported via Extended
    Simple Mail Transfer Protocol [SMTP].  Thus, the MMS MM3 interface
    supports the ability to exchange voice messages between an MMS
    system and a voice mail system.  Note that such use is distinct from
    voice media being part of a user-composed multimedia message.

    Note that MM3 can also be used for interworking with "external"
    (non-MMS) systems other than Internet mail, such as Short Messaging
    Service (SMS) and access to external mail stores (such as a voice
    mail system).  This specification does not address these other uses
    or sub-interfaces of MM3; it is only concerned with Internet mail
    interworking and specifically exchange of messages.

    All MM3 Stage 2 [Stage_2] functions are supported except for reply
    charging.  Sender address hiding may be used but is not recommended
    without security assurances which are beyond the scope of this
    specification (see Section 3).


1.2 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].

    Note that in the text of this document, a distinction is made
    between use of "SMTP" or "Simple Mail Transfer Protocol", and
    "ESMTP" or "Extended Simple Mail Transfer Protocol": when the term
    "ESMTP" or "Extended" is used, it indicates use of extended features
    of SMTP; that is, those beyond the facilities of RFC 821. (These
    extended facilities may be in RFC 2821 or in other RFCs, as
    indicated by the specific RFC reference used; note that the name of
    the RFC 2821 reference is "SMTP" because that is the official title
    of the RFC.)





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1.3 Definitions

    --------------------|----------------------------------------------
    Anonymous Remailer  |A service which accepts messages and resends
                        |them to their intended recipient, masking
                        |information about the original sender.
    --------------------|----------------------------------------------
    Body                |The portion of an SMTP message's Content
                        |following the Header (that is, following the
                        |first blank line).  The Body may contain
                        |structured parts and sub-parts, each of which
                        |may have their own Header and Body.  The Body
                        |contains information intended for the message
                        |recipient (human or software).
    --------------------|----------------------------------------------
    Content             |The portion of an SMTP message that is
                        |delivered.  The Content consists of a Header
                        |and a Body.
    --------------------|----------------------------------------------
    Disposition Report  |Feedback information to an originator User
                        |Agent by a recipient User  Agent about
    Message Disposition |handling of an original message.  This may
       Notification     |include notification that the message was or
                        |was not read, was deleted unread, etc.
    --------------------|----------------------------------------------
    Envelope            |The portion of an SMTP message not included in
                        |the Content; that is, not in the Header nor in
                        |the Body.  Envelope information only exists
                        |while the message is in transit, and contains
                        |information used by SMTP agents (MTAs).
    --------------------|----------------------------------------------
    Header              |The first part of an SMTP message's Content.
                        |The Header is separated from the Body by a
                        |blank line.  The Header consists of Fields
                        |(such as "To:"), also known as Header Fields
                        |or Headers.  The message Header contains
                        |information used by User Agents.
    --------------------|----------------------------------------------
    Gateway Function    |An agent which acts as both MMSC and MTA
                        |and/or MSA.
    --------------------|----------------------------------------------
    User Agent          |An MMS or Email user agent
    --------------------|----------------------------------------------








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1.4 Abbreviations

    --------|----------------------------------------------------------
    ESMTP   |Extended Simple Mail Transfer Protocol.  The use of
            |features and capabilities added to SMTP since RFC 821.
    --------|----------------------------------------------------------
    MSA     |Message Submission Agent.  A server which accepts messages
            |from User Agents and processes them; either delivering
            |them locally or relaying to an MTA.
    --------|----------------------------------------------------------
    MTA     |Mail Transfer Agent.  A server which implements [SMTP].
    --------|----------------------------------------------------------


1.5 Assumptions

    It is assumed that the reader is already familiar with the contents
    of the 3GPP2 MMS Specification Overview [Overview], MMS Stage 1
    (requirements) [Stage_1] and Stage 2 (architecture and abstract
    messages) [Stage_2], and 3GPP/3GPP2 Stage 3 (protocols) [Stage_3]
    documents.  It is also assumed that the reader is familiar with
    Internet mail, especially RFC 2821 [SMTP] and RFC 2822 [Msg-Fmt].


2 Mapping Between MMS and Internet Mail

    This section defines the interworking between MMS Relay/Servers and
    External Servers using native ESMTP.  That is, information elements
    are exchanged using standard Internet Message [Msg-Fmt] header
    fields and standard [SMTP] elements.

    SMTP and Internet mail extensions are used for features such as
    delivery reports, message expiration, discovery of server support
    for optional features, etc.


2.1 Mapping Specification

2.1.1 MMS to Internet Mail

    When sending a message to an Internet mail system the MMS
    Relay/Server MUST convert the MM if required, and MUST comply with
    the requirements of [SMTP] (for example, use of a null return-path
    for automatically-generated messages).

    The MMS Relay/Server SHOULD use the information elements associated
    with the MM to define the control information (Internet Message
    header fields and ESMTP values) needed for the transfer protocol.



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    Section 2.1.3 lists the mappings between X-Mms-* headers and
    Internet Message header fields and ESMTP values.

    Delivery and read report MMs SHOULD be converted to standard
    Internet Message report format (multipart/report).  In addition to
    converting Internet Message reports, the MMS Relay/Server MUST
    generate delivery and read report MMs for received messages as
    appropriate.  See section 2.1.4 for more information.


2.1.2 Internet Mail to MMS

    When receiving a message from an Internet mail system the MMS
    Relay/Server MAY convert incoming messages to the MM format used
    within the receiving system.

    The MMS Relay/Server MAY convert control information received from
    the Internet mail server into appropriate information elements of an
    MM.

    Section 2.1.3 lists the mappings between X-Mms-* headers and
    Internet Message header fields and ESMTP values.

    Standard Internet Message report format (multipart/report) messages
    MAY be converted to delivery or read report MMs, as appropriate.  In
    addition to converting report MMs, the MMS Relay/Server MUST
    generate standard Internet Message delivery and disposition reports
    for received Internet messages as appropriate.  See section 2.1.4
    for more information.






















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2.1.3 MMS Information Element Mappings

    The mappings between MMS elements and ESMTP/Internet Message
    elements (either [SMTP] parameters, [Msg-Fmt] headers, or both) are
    summarized in the table below, and detailed in subsequent sections.
    The "MMS Headers" are from [OMA-MMS].  Note that only information
    elements which need to be mapped are listed. [Msg-Fmt] headers not
    listed here SHOULD be passed unaltered

2.1.3.1 Table 1:  MM3 Mappings

    =================|=================|================|==============
    Information Elem |[SMTP] Element   |[Msg-Fmt] Header|MMS Header
    =================|=================|================|==============
    3GPP MMS Version |N/A              |N/A             |X-Mms-Version:
                     |                 |                |
    _________________|_________________|________________|______________
    Message Type     |N/A              |N/A             |X-Mms-Message-
    (of PDU)         |                 |                |   Type:
    _________________|_________________|________________|______________
    Transaction ID   |N/A              |N/A             |X-Mms-Transact
                     |                 |                |   ion-Id:
    _________________|_________________|________________|______________
    Message ID       |ENVID [DSN-SMTP] |Message-ID:     |X-Mms-Message-
                     |                 |                |   Id:
                     |                 |                |Message-ID:
    _________________|_________________|________________|______________
    Recipient        |RCPT TO          |To:, Cc:, or    |To:, Cc:, Bcc:
    address(es)      |address(es)      |omitted (Bcc)   |
    _________________|_________________|________________|______________
    Sender's address |MAIL FROM        |From: (MAY set  |From:
                     |address if       |to locally-gen- |
                     |user-originated; |erated value    |
                     |MUST set MAIL    |to hide sender  |
                     |FROM to null     |identity in     |
                     |("<>") for all   |anonymous mes-  |
                     |automatically-   |sages when      |
                     |generated MMs    |receiving sys-  |
                     |                 |tem does not    |
                     |                 |support anony-  |
                     |                 |mous messages)  |
    _________________|_________________|________________|______________
    Content type     |N/A              |Content-Type:   |Content-type:
                     |                 |                |
                     |                 |For voice mes-  |
                     |                 |sages compliant |
                     |                 |to [VPIM], see  |
                     |                 |Note 2          |
    =================|=================|================|==============


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    =================|=================|================|==============
    Information Elem |RFC 2821 Element |RFC 2822 Header |MMS Header
    =================|=================|================|==============
    Message class    |Class=auto:      |MAY set 'Prece  |X-Mms-Message-
                     |MUST set MAIL    |   dence: bulk' |   Class:
                     |FROM to null     |on class=auto   |
                     |("<>").          |                |
    _________________|_________________|________________|______________
    Date and time    |N/A              |Date:           |Date:
    of submission    |                 |                |
    _________________|_________________|________________|______________
    Time of expiry   |DELIVER-BY       |N/A             |X-Mms-Expiry:
                     |[Deliver-By]     |                |
    _________________|_________________|________________|______________
    Earliest deliv-  |(only for submis-|N/A             |X-Mms-Delivery
    ery time         |sion; not relay) |                |   -Time:
    _________________|_________________|________________|______________
    Delivery report  |DSN [DSN-SMTP]   |N/A             |X-Mms-Delivery
    request          |SHOULD also      |                |   -Report:
                     |specify recip-   |                |
                     |ient address as  |                |
                     |ORCPT; SHOULD    |                |
                     |also specify     |                |
                     |ENVID            |                |
    _________________|_________________|________________|______________
    Importance (a/k/a|N/A              |Importance:     |X-Mms-
    "priority")      |                 |X-Priority:     |   Priority:
                     |                 |                |
                     |                 |                |
    _________________|_________________|________________|______________
    Sender visib-    |X-ANONYMOUS (see |N/A             |X-Mms-Sender-
    ility            |text below)      |                |   Visibility:
    _________________|_________________|________________|______________
    Read reply       |N/A              |Disposition-    |X-Mms-Read-
    request          |                 |   Notification |   Reply:
                     |                 |   -To: [MDN]   |
    _________________|_________________|________________|______________
    Reply-charging   |(not currently   |(not currently  |X-Mms-Reply-
    permission       |supported)       |supported)      |   Charging:
    _________________|_________________|________________|______________
    Reply-charging   |(not currently   |(not currently  |X-Mms-Reply-
    permission       |supported)       |supported)      |   Charging-
    deadline         |                 |                |   Deadline:
    _________________|_________________|________________|______________
    Reply-charging   |(not currently   |(not currently  |X-Mms-Reply-
    permission       |supported)       |supported)      |   Charging-
    limitation       |                 |                |   Size:
    =================|=================|================|==============



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    =================|=================|================|==============
    Information Elem |RFC 2821 Element |RFC 2822 Header |MMS Header
    =================|=================|================|==============
    Reply-charging   |(not currently   |(not currently  |X-Mms-Reply-
    usage request    |supported)       |supported)      |   Charging-
                     |                 |                |   Id:
    _________________|_________________|________________|______________
    Reply-charging   |(not currently   |(not currently  |X-Mms-Reply-
    usage reference  |supported)       |supported)      |   Charging:
    _________________|_________________|________________|______________
    Subject          |N/A              |Subject:        |Subject:
    _________________|_________________|________________|______________
    Forward counter  |N/A              |Resent-Count:   |(Not sup-
                     |                 |                |ported)
    _________________|_________________|________________|______________
    Previously-sent- |N/A              |Resent-From:    |X-Mms-Previous
    by               |                 |                |   ly-Sent-By:
    _________________|_________________|________________|______________
    Previously-sent- |N/A              |Resent-Date:    |X-Mms-
    date and-time    |                 |                |   Previously-
                     |                 |                |   Sent-Date:
    _________________|_________________|________________|______________
    Hop/host trace   |N/A              |Received:       |(Not sup-
                     |                 |                |ported)
    _________________|_________________|________________|______________
    Sensitivity      |N/A              |Sensitivity: see|N/A
                     |                 |Note 1          |
    _________________|_________________|________________|______________
    Content          |N/A              |<message body>  |<message body>
    =================|=================|================|==============

    Note 1:  The [VPIM] 'Sensitivity' header element indicates the
    privacy requested by the message originator (values are ÓpersonalÔ
    or ÓprivateÔ); a message recipient MUST NOT forward a message with a
    'Sensitivity' header.

    Note 2:  A MIME-Version header with a comment of ÓVoice 2.0Ô
    indicates that the voice message conforms to [VPIM].


2.1.3.2 Conversion of messages from MMS to Internet format

    3GPP MMS Version

    The 'X-Mms-Version:' header, if present, SHOULD be removed.






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    Message Type (of PDU)

    The 'X-Mms-Message-Type:' header, if present, SHOULD be removed.

    Transaction ID

    The 'X-Mms-Transaction-Id:' header, if present, SHOULD be removed.

    Message ID

    An 'X-Mms-Message-Id:' header, if present, SHOULD be retained.

    The 'Message-Id:' header MUST be retained.  If not present it MUST
    be created, with a unique value.  If an 'X-Mms-Message-Id:' header
    is present and a 'Message-Id:' header is not, the value of the
    'X-Mms-Message-Id:' header MAY be used in creating the 'Message-Id:'
    header.

    The message ID SHOULD be transmitted in the ESMTP envelope as the
    ENVID parameter, as specified in [DSN-SMTP].

    Recipient(s) address

    The address of each recipient MUST be transmitted in the SMTP
    envelope as a RCPT TO value.  All disclosed recipients SHOULD also
    appear in a 'To:' or 'Cc:' header.  At least one 'To:' or 'Cc:'
    header MUST be present.  If all recipients are undisclosed, a 'To:'
    header MAY be created that contains a comment, for example 'To:
    (undisclosed recipients)'.  The 'To:' header SHOULD NOT appear more
    than once.  The 'Cc:' header SHOULD NOT appear more than once.

    Each recipient address MUST obey the length restrictions per [SMTP].

    Current Internet message format requires that only 7-bit US-ASCII
    characters be present in addresses.  Other characters (for example,
    non-7-bit characters in a phrase part of an address header) MUST be
    encoded according to [Hdr-Enc].  Note that it would be possible to
    define an SMTP extension to permit transmission of unencoded 8-bit
    characters, but in the absence of such an extension [Hdr-Enc] MUST
    be used.

    Sender address

    The address of the message sender SHOULD appear in the 'From:'
    header, unless address hiding has been requested.  If address hiding
    has been requested, the 'From:' header MAY contain a comment to this
    effect, for example, 'From: (anonymous sender)'.




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    The address of the message sender for all user-generated messages
    ('X-Mms-Message-Class:  Personal') SHOULD be transmitted in the SMTP
    envelope as the MAIL FROM value unless address hiding has been
    requested and the receiving server is not known and trusted to
    support address hiding.

    The 'From:' header and the MAIL FROM value MAY be set to a
    locally-generated value to hide the sender identity in anonymous
    messages when the receiving system does not support anonymous
    messages.  Locally generated addresses MAY be internally mapped to
    the actual address to allow replies to anonymous messages, but such
    mapping is beyond the scope of this specification.

    Because of the risk of mail loops, it is critical that the MAIL FROM
    be set to null ("<>") for all automatically-generated MMs (such as
    'X-Mms-Message-Class:  Auto').  The MAIL FROM value MUST be set to
    null for all automatically-generated messages.  This includes
    reports, "out-of-office" replies, etc.

    Current Internet message format requires that only 7-bit US-ASCII
    characters be present in addresses.  Other characters (for example,
    non-7-bit characters in a phrase part of an address header) MUST be
    encoded according to [Hdr-Enc].  Note that it would be possible to
    define an SMTP extension to permit transmission of unencoded 8-bit
    characters, but in the absence of such an extension [Hdr-Enc] MUST
    be used.

    The sender address MUST obey the length restrictions of [SMTP].

    Content type

    The 'Content-Type:' header SHOULD be preserved.  Content types not
    in widespread use in the Internet MAY be converted into those that
    are, when such conversion can be done without significant loss of
    content.  For example, SMIL messages MAY be converted into
    widely-supported multipart/related with multipart/html.  When such
    conversion is done, the 'Content-Type:' header MUST be updated if it
    is no longer correct.

    Message class

    The 'X-Mms-Message-Class:' header MAY be retained.  A 'Precedence:
    bulk' header MAY be inserted for class=auto or class=advertisement.
    See 'Sender Address' above. (Class=personal and class=informational
    do not require special handling.)






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    Time of Expiry

    The 'X-Mms-Expiry:' header, if present, SHOULD be removed.

    The remaining time until the message is considered expired SHOULD be
    transmitted in the ESMTP envelope by using the DELIVER-BY extension,
    as specified in [Deliver-By].

    Note that the ESMTP DELIVER-BY extension carries time remaining
    until expiration; each server decrements the value by the amount of
    time it has possessed the message.  The 'X-Mms-Expiry:' header may
    contain either the absolute time at which the message is considered
    expired or the relative time until the message is considered
    expired.

    Earliest delivery time

    The 'X-Mms-Delivery-Time:' header, if present, SHOULD be removed.

    Future delivery is a message submission, not message relay feature.

    Delivery report request

    Requests for delivery status notifications (DSNs) SHOULD be
    transmitted in the ESMTP envelope by using the DSN extension as
    specified in [DSN-SMTP] to request "success" or "none" notification
    (depending on the value of the 'X-Mms-Delivery-Report' header).
    When the NOTIFY extension is used, the unaltered recipient address
    SHOULD be transmitted as the ORCPT value, and the original message
    ID SHOULD be transmitted as the ENVID value.

    The 'X-Mms-Delivery-Report:' header, if present, SHOULD be removed.

    Importance

    The message sender's importance value (also called "priority",
    although this can be confused with class-of-service values) SHOULD
    be transmitted using an 'Importance:' header (although currently not
    all Internet mail clients support this header).

    An 'X-Priority:' header MAY be used in addition.  Although not
    standardized, most email applications support the 'X-Priority:'
    header, and use an 'X-Priority' value of 3 for messages with
    "normal" priority.  More important messages have lower values and
    less important message have higher values.  In most cases, urgent
    messages have an X-Priority value of 1.





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    Suggested mappings:

2.1.3.2.1 Table 2:  Importance Mappings (MMS to Internet Message)

        ---------------------------|------------------
        'X-Mms-Priority: High'     |'Importance: High'
        ---------------------------|------------------
        'X-Mms-Priority: Normal'   |[omit]
        ---------------------------|------------------
        'X-Mms-Priority: Low'      |'Importance: Low'
        ---------------------------|------------------

    Normal priority messages should omit the 'Importance:' header.

2.1.3.2.2 Table 3:  X-Priority Mappings (MMS to Internet Message)

        ---------------------------|----------------------
        'X-Mms-Priority: High'     |'X-Priority: 2 (high)'
        ---------------------------|----------------------
        'X-Mms-Priority: Normal    |[omit]
        ---------------------------|----------------------
        'X-Mms-Priority: Low       |'X-Priority: 4 (low)'
        ---------------------------|----------------------

    Normal priority messages SHOULD omit the 'X-Priority:' header.

    The 'X-Mms-Priority:' header, if present, SHOULD be removed.

    Sender visibility

    Requests for sender address hiding may be transmitted in the ESMTP
    envelope by using the X-ANONYMOUS extension.  The request is made by
    adding "X-ANONYMOUS" to the MAIL FROM command.  Servers which
    support address hiding may advertise this by including X-ANONYMOUS
    in their EHLO response.

    Note that even if servers claim to support address hiding, there is
    no technical guarantee that it will be properly honored; servers
    MUST NOT trust other servers to support this without a basis which
    is beyond the scope of this specification (such as business
    relationships).

    The 'X-Mms-Sender-Visibility:' header, if present, SHOULD be
    removed.

    Read reply request





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    A request for a read reply SHOULD be transmitted using a
    'Disposition-Notification-To:' header as specified in [MDN].

    The 'X-Mms-Read-Reply:' header, if present, SHOULD be removed.

    Reply-charging

    Reply charging permission and acceptance are complex issues
    requiring both user agent and server support.  Misapplied reply
    charging may cause incorrect billing.  Until the security issues
    have been properly addressed, reply charging SHOULD NOT be honored
    when using this interface.

    The 'X-Mms-Reply-Charging:', 'X-Mms-Reply-Charging-Deadline:',
    'X-Mms-Reply-Charging-Size:', and 'X-Mms-Reply-Charging-Id:' headers
    MAY be removed.  Messages containing a reply-charging usage request
    ('X-Mms-Reply-Charging-Id:' and 'X-Mms-Reply-Charging: accepted' or
    'X-Mms-Reply-Charging: accepted (text only)' headers) SHOULD be
    rejected.

    Subject

    The 'Subject:' header MUST be preserved.  Current Internet message
    format requires that only 7-bit US-ASCII characters be present.
    Other characters must be encoded according to [Hdr-Enc].  Note that
    it would be possible to define an SMTP extension to permit
    transmission of unencoded 8-bit characters, but in the absence of
    such an extension [Hdr-Enc] must be used.

    Resending/Forwarding

    In MMS a message may be resent or forwarded, the difference being
    that if the message has been downloaded then sending it to another
    address is considered forwarding, while sending a message that has
    not been downloaded is considered to be resending.

    In Internet mail there are two primary ways of sending a previously
    received message to a new recipient: forwarding and resending.
    Forwarding is when a user creates a new message containing the
    original message, either simply embedded within the text, or
    delineated.  Embedded messages generally have each original line
    preceded by a quote symbol ('>'), surround the original text with a
    preceding and trailing line which starts with hyphens as per
    [Msg-Encap], such as '--- begin forwarded text' and '--- end
    forwarded text', or encapsulate the original message as a
    'message/rfc822' content type, perhaps within a 'multipart/mixed'
    message. (This last method offers more robust delineation.)
    Resending is when the original message is unaltered except for the
    addition of 'Resent-' headers to explain the resending to the new


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    recipient.

    A message may be resent more than once; each time new 'Resent-'
    headers SHOULD be added at the top of the message.  Thus, if more
    than one series of 'Resent-' headers are present, the original
    series is the last; the most recent is the first.

    Forward counter

    The 'Resent-Count:' header MAY be used to track the number of times
    the message has been resent.  Note that loop control is often done
    by counting 'Received' headers, which are more general than
    'Resent-' headers.

    Previously-sent Information

    A 'Resent-From:' header MAY be added to indicate the address of the
    user who directed the message to be resent.

    A 'Resent-Date:' header SHOULD be added to indicate the time and
    date that the message was resent.

    Any 'X-Mms-Previously-Sent-By:' and 'X-Mms-Previously-Sent-Date'
    headers, if present, SHOULD be removed.  The information contained
    in them SHOULD be translated into 'From:', 'Resent-To:',
    'Resent-From:', 'Resent-Date:', and 'Resent-Count:' headers.  The
    original sender of the message SHOULD appear in the 'From:' header;
    the original recipient(s) SHOULD appear in the 'To:' header; the
    time and date the message was originally sent SHOULD appear in the
    'Date:' header.  The most recent sender SHOULD appear in the
    top-most 'Resent-From:' header; the most recent recipient(s) SHOULD
    appear in the top-most 'Resent-To:' header; the time and date the
    message was most recently sent SHOULD appear in the top-most
    'Resent-Date:' header.

    'Received:' Headers

    Each system that processes a message SHOULD add a 'Received:' header
    as per [SMTP].  A message MAY be rejected if the number of
    'Received:' headers exceeds a locally-defined maximum, which MUST
    conform to [SMTP] section 6.2 and SHOULD be no less than 100.

    Privacy

    Note that MMS systems do not currently support the 'Privacy' header
    field as described by [VPIM].





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    Content

    The message content appears in the message body.  Note that Internet
    message format requires that line-endings be encoded as CR LF, thus
    charset encodings that do not have this property cannot be used in
    text/* body parts. (They MAY be used in other body parts, but only
    when they are suitable encoded or when binary transmission has been
    negotiated.) In particular, MMS allows UTF-16, while Internet
    message format does not.  UTF-16 encoding MUST be translated to
    UTF-8 or another charset and encoding which is suitable for use in
    Internet message format/protocols.


2.1.3.3 Conversion of messages from Internet to MMS format

    3GPP MMS Version

    An 'X-Mms-Mms-Version:' header SHOULD be added.

    Message Type (of PDU)

    An 'X-Mms-Message-Type:' header SHOULD be used in accordance with
    the specific MMS interface (e.g., MM1, MM4).

    Transaction ID

    An 'X-Mms-Transaction-Id:' header SHOULD be used in accordance with
    the specific MMS interface (e.g., MM1, MM4).

    Message ID

    The 'Message-Id:' header MUST be retained.  If not present it MUST
    be created, with a unique value.  If the 'Message-Id:' header does
    not exist, but the SMTP envelop contains an ENVID value (as
    specified in [DSN-SMTP]), it MAY be used to construct the value.

    Recipient(s) address

    'To:' and 'Cc:' headers MUST be retained.

    Each recipient contained in the SMTP envelope (RCPT TO values) MUST
    be considered a recipient of the message.  Recipients who appear in
    address headers but not the SMTP envelope MUST be ignored.
    Recipients who appear in the [SMTP] envelope but do not appear in
    headers are considered "blind" (Bcc) recipients; such recipients
    MUST NOT be added to message headers (including address and trace
    headers) unless there is only one recipient total.




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    Sender address

    The 'From:' header MUST be retained.

    If address hiding has been requested, the 'From:' header MAY contain
    a comment to this effect, for example, 'From: (anonymous sender)'.

    Content type

    The complete 'Content-Type:' header (including any parameters)
    SHOULD be preserved.

    Message class

    An X-Mms-Message-Class: personal' header SHOULD be created for all
    received messages with a non-null return path (MAIL FROM value in
    the SMTP envelope).  An X-Mms-Message-Class: auto' header MAY be
    created for messages with a null return path.

    Time of Expiry

    An 'x-Mms-Expiry:' header SHOULD be created if the message contains
    a relative time to expiration in the DELIVER-BY extension, as
    specified in [Deliver-By].

    Earliest delivery time

    An 'X-Mms-Delivery-Time:' header SHOULD NOT be created.  If a
    message arrives via ESMTP relay containing an earliest time of
    delivery in the AFTER extension, it MAY be rejected.  If a message
    is submitted via Message Submission [Submission] containing an
    earliest time of delivery in the AFTER extension, it MUST either be
    retained until the delivery time arrives, or it may be immediately
    rejected.  It MUST NOT be delivered or further relayed prior to the
    delivery time.

    Delivery report request

    An 'X-Mms-Delivery-Report:' header SHOULD be created for messages
    which request 'success' or 'none' delivery status notification by
    use of the DSN extension as specified in [DSN-SMTP].  Requests for
    'delay' notifications or non-default actions, such as that only the
    message headers should be returned, cannot be mapped onto MMS
    headers and thus SHOULD be ignored.

    Priority





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    An 'X-Priority:' or 'Importance:' header, if present, SHOULD be
    replaced with an 'X-Mms-Priority:' header.  Suggested mappings:

2.1.3.3.1 Table 4:  Priority Mappings (Internet Message to MMS)

        -------------------------------|----------------------
        'X-Priority: 1 (highest)'      |'X-Mms-Priority: High'
        -------------------------------|----------------------
        'X-Priority: 2 (high)'         |'X-Mms-Priority: High'
        -------------------------------|----------------------
        'Importance: High'             |'X-Mms-Priority: High'
        -------------------------------|----------------------
        'X-Priority: 3 (normal)'       |      [omitted]
        -------------------------------|----------------------
        'Importance: Normal'           |      [omitted]
        -------------------------------|----------------------
        'X-Priority: 4 (low)'          |'X-Mms-Priority: Low'
        -------------------------------|----------------------
        'Importance: Low'              |'X-Mms-Priority: Low'
        -------------------------------|----------------------
        'X-Priority: 5 (lowest)'       |'X-Mms-Priority: Low'
        -------------------------------|----------------------

    Normal priority messages SHOULD omit the 'X-Mms-Priority:' header.

    Sender visibility

    Requests for sender address hiding MAY be received in the SMTP
    envelope by the X-ANONYMOUS extension.  Servers which support
    address hiding MAY advertise this by including X-ANONYMOUS in their
    EHLO response.  A message received which includes X-ANONYMOUS in the
    MAIL FROM command has requested address hiding.

    Note that even if servers claim to support address hiding, there is
    no technical guarantee that it will be properly honored; servers
    SHOULD NOT trust other servers to support this without a basis which
    is beyond the scope of this specification (such as business
    relationships).

    Requests for sender address hiding MAY be reflected in the created
    MM by adding an 'X-Mms-Sender-Visibility:' header.

    Read reply request

    A request for a read reply contained in a
    'Disposition-Notification-To:' header as specified in [MDN] SHOULD
    be replaced with an 'X-Mms-Read-Reply:' header.




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    Subject

    The 'Subject:' header MUST be preserved.

    Resending/Forwarding

    One or more sets of 'Resent-' headers, if present, SHOULD be mapped
    to 'To:', 'From:', 'Date:', and 'X-Mms-Previously-Sent-' headers.

    'Received:' Headers

    Each system that processes a message SHOULD add a 'Received:' header
    as per [SMTP].  A message MAY be rejected if the number of
    'Received:' headers exceeds a locally-defined maximum, which MUST
    conform to [SMTP] section 6.2 and SHOULD be no less than 100.

    Sensitivity

    The 'Sensitivity:' header field (value = ÓpersonalÔ or ÓprivateÔ)
    [VPIM] indicates the desire of a voice message originator to send
    the message contents to the original recipient list with assurance
    that the message will not be forwarded further by either the
    messaging system or the actual message recipient(s).  Since
    sensitivity is not an MMS feature, any messages which contain a
    'Sensitivity:' header SHOULD NOT be sent to an MMS system.  An
    appropriate extended error response code [RESP] SHOULD be used in
    the associated negative delivery status report.

    Content

    The message content appears in the message body.


2.1.4 Report Generation and Conversion

    Internet Message systems use the multipart/report MIME type for
    delivery and disposition reports (often called "read reports") as
    specified in [Report-Fmt].  This format is a two- or three-part MIME
    message; one part is a structured format describing the event being
    reported in an easy-to-parse format.  Specific reports have a format
    which is built on [Report-Fmt].  Delivery reports are specified in
    [DSN-Msg].  Message disposition reports, which include read reports,
    are specified in [MDN].

    By contrast, MMS reports are plain text, with no defined structure
    specified.  This makes it difficult to convert from an MMS report to
    a standard Internet report.




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    An MMS Relay/Server supporting Internet Message exchange using MM3
    MUST convert reports received from one side (MMS or Internet mail)
    destined for the other.  In addition, reports MUST be generated as
    appropriate for messages received from either side of the MM3
    interface.  For example, if an MM to be sent via MM3 is not
    deliverable, a delivery status MM shall be generated.  Likewise, if
    an Internet message is received via MM3 that cannot be further
    relayed or delivered, a delivery status report [DSN-Msg] MUST be
    generated.

    When creating delivery or disposition reports from MMS reports, the
    MMS report should be parsed to determine the reported event and
    time, status, and the headers of the referenced (original) message.
    These elements, once determined, are used to populate the subparts
    of the delivery or disposition report.  The first subpart is of type
    text/plain, and contains a human-readable explanation of the event.
    This text may include a statement that the report was synthesized
    based on an MMS report.  The second subpart is of type
    report/delivery-status (for delivery reports) or
    report/disposition-notification (for disposition reports).  This
    second part contains a structured itemization of the event.  The
    third subpart is of type message/rfc822 and includes the headers and
    optionally the body of the referenced (original) message.


2.1.4.1 Delivery Report Mapping from MMS to Internet Message

    The following table maps information elements from MMS delivery
    reports to the format specified in [DSN-Msg].

2.1.4.1.1 Table 5:  Delivery Report Mappings (MMS to Internet Message)

======================|============|===================================
Information Element   |MMS Delivery|[DSN-Msg] Element
                      |Report Elem |
======================|============|===================================
ID of message whose   |Message-Id: |'Original-Envelope-ID' field of
delivery status is    |            |per-message fields (use value of
being reported        |            |ENVID from ESMTP envelope if avail-
                      |            |able, 'Message-ID:' otherwise).
----------------------|------------|-----------------------------------
Recipient address of  |From:       |'Final-Recipient' field of the
the original message  |            |per-recipient section
(object of delivery   |            |
report)               |            |
======================|============|===================================





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======================|============|===================================
Information Element   |MMS Delivery|[DSN-Msg] Element
                      |Report Elem |
======================|============|===================================
Destination address of|To:         |'To:' header field value of top-
report                |            |level.
                      |            |
                      |            |Value taken from [SMTP] envelope
                      |            |return-path of message being
                      |            |reported, not its 'From:' header
                      |            |field.
----------------------|------------|-----------------------------------
Date and time the     |Date:       |'Date:' header field value of top-
message was handled   |            |level
----------------------|------------|-----------------------------------
Delivery status of    |X-Mms-      |Action and Status fields of
original message      |   Status:  |per-recipient section.
                      |            |
                      |            |The 'Action' field indicates if the
                      |            |message was delivered.
                      |            |
                      |            |For failed delivery an appropriate
                      |            |'Status' value shall be included
                      |            |per [DSN-Msg].
                      |            |
                      |            |The Action field is set to one of
                      |            |the following values:
                      |            |
                      |            |* delivered (used for MMS status
                      |            |values 'retrieved' and 'rejected',
                      |            |depending on 'Status' code).
                      |            |
                      |            |* failed (used for MMS status
                      |            |values 'expired' and 'unreachable')
                      |            |
                      |            |* delayed MAY be used for MMS
                      |            |status value 'deferred'
                      |            |
                      |            |* relayed (used for MMS status
                      |            |value 'indeterminate')
                      |            |
                      |            |* expanded (SHOULD NOT be used)
----------------------|------------|-----------------------------------
Status Text           |            |Text in first part (human-readable
                      |            |part)
----------------------|------------|-----------------------------------





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    When an MMS Relay/Server generates a [DSN-Msg] in response to a
    message received using [SMTP] on MM3:

    * Top-level header field 'To:' SHOULD be the [SMTP] return-path of
    the message whose status is being reported.

    * Top-level header field 'From:' SHOULD be the address of the
    recipient that the delivery-report concerns.

    * The first part of the [DSN-Msg] SHOULD include the MM Status Text
    field that would have been generated for an MM1 delivery-report.


2.1.4.2 Delivery Report Mapping from Internet Message to MMS

    The following table maps information elements from a delivery report
    as specified in [DSN-Msg] to the format of an MMS delivery report.

2.1.4.2.1 Table 6:  Delivery Report Mappings (Internet Message to MMS)

===================|==================|================================
Information Element|MMS Delivery      |[DSN=Msg] Element
                   |Report Element    |
===================|==================|================================
ID of the original |Message-Id:       |'Original-Envelope-ID' field of
message (object of |                  |per-message fields.  If not
delivery report)   |                  |available, the 'Message-ID'
                   |                  |header field of the message
                   |                  |being reported, if included in
                   |                  |the third part, may be
                   |                  |substituted.
-------------------|------------------|--------------------------------
Recipient address  |From:             |If available, the 'Original
of the original    |                  |-Recipient' field of the per-
message (object of |                  |recipient section should be
delivery report)   |                  |used; otherwise the 'Final-
                   |                  |Recipient' field of the per-
                   |                  |recipient section is used
-------------------|------------------|--------------------------------
Destination address|To:               |'To:' header field value of
of report          |                  |top-level.
                   |                  |
                   |                  |Value taken from [SMTP] envelope
                   |                  |return-path of message being
                   |                  |reported, not its 'From:' header
                   |                  |field.
===================|==================|===================================




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===================|==================|================================
Information Element|MMS Delivery      |[DSN=Msg] Element
                   |Report Element    |
===================|==================|================================
Date and time the  |Date:             |'Date:' header field value of
message was handled|                  |top-level
-------------------|------------------|--------------------------------
Delivery status of |X-Mms-Status:     |'Action' and 'Status' fields of
original message   |                  |per-recipient section
                   |Set to one of the |
                   |following values: |
                   |                  |
                   |'retrieved' (used |
                   |for 'Action' value|
                   |'delivered').     |
                   |                  |
                   |'unreachable'     |
                   |(used for 'Action'|
                   |value 'failed')   |
                   |                  |
                   |'forwarded' (used |
                   |for 'Action' value|
                   |'relayed')        |
                   |                  |
                   |'deferred' MUST   |
                   |NOT be used       |
                   |(ignore DSNs with |
                   |'Action' value    |
                   |'delayed')        |
-------------------|------------------|--------------------------------
Status Text        |                  |Text in first part (human-
                   |                  |readable part)
===================|==================|================================


















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2.1.4.3 Read Report Mapping from MMS to Internet Message

    The following table maps information elements from MMS read reports
    to the format specified in [MDN].

2.1.4.3.1 Table 7:  Read Report Mappings (MMS to Internet Message)

======================|============|===================================
Information Element   |MMS Delivery|[DSN-Msg] Element
                      |Report Elem |
======================|============|===================================
ID of the original    |Message-Id: |'Original-Envelope-ID' field (use
message (object of    |            |value of ENVID from ESMTP envelope
read report)          |            |if available, 'Message-ID:'
                      |            |otherwise).
----------------------|------------|-----------------------------------
Recipient address of  |From:       |'Final-Recipient' field
the original message  |            |
----------------------|------------|-----------------------------------
Destination address of|To:         |'To:' header field value of top-
report                |            |level.
                      |            |
                      |            |Value taken from 'Disposition-
                      |            |Notification-To:' header field of
                      |            |message being reported, not its
                      |            |'From:' header field.
----------------------|------------|-----------------------------------
Date and time the     |Date:       |'Date:' header field value of top-
message was handled   |            |level
----------------------|------------|-----------------------------------
Disposition of message|X-Mms-Read- |Disposition-field
being reported        |   Status:  |
                      |            |For MMS-Read-Status value 'read',
                      |            |use 'disposition-type' value
                      |            |'displayed'; for MMS-Read-Status
                      |            |value 'Deleted without being read',
                      |            |use 'disposition-type' value
                      |            |'deleted')
----------------------|------------|-----------------------------------
Status Text           |            |Text in first part (human-readable
                      |            |part)
======================|============|===================================

    When an MMS Relay/Server generates an [MDN] in response to a message
    received using ESMTP on MM3:






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    * Top-level header field 'To:' SHOULD be the value of the
    'Disposition-Notification-To:' header field of the message whose
    disposition is being reported .

    * Top-level header field 'From:' SHOULD be the address of the
    recipient that the read report concerns.


2.1.4.4 Disposition Report Mapping from Internet Message to MMS

    The following table maps information elements from a disposition
    report as specified in [MDN] to the format of an MMS read report.

2.1.4.4.1 Table 8:  Disposition Report Mappings (Internet Message to
     MMS)

===================|==================|================================
Information Element|MMS Read Report   |[DSN=Msg] Element
                   |Element           |
===================|==================|================================
ID of the original |Message-Id:       |'Original-Envelope-ID' field
message (object of |                  |
disposition report)|                  |
-------------------|------------------|--------------------------------
Recipient address  |From:             |'Final-Recipient' field
of the original    |                  |
message            |                  |
-------------------|------------------|--------------------------------
Destination address|To:               |'To:' header field value of
of report          |                  |top-level.
                   |                  |
                   |                  |Value taken from 'Disposition-
                   |                  |Notification-To:' header field
                   |                  |of message being reported, not
                   |                  |its 'From:' header field.
-------------------|------------------|--------------------------------
Date and time the  |Date:             |'Date:' header field value of
message was handled|                  |top-level
===================|==================|================================












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===================|==================|================================
Information Element|MMS Read Report   |[DSN=Msg] Element
                   |Element           |
===================|==================|================================Disposition of     |X-Mms-Read-Status:|disposition-field
message being      |                  |
reported           |Set to one of the |
                   |following values: |
                   |                  |
                   |'read' (used for  |
                   |disposition-type  |
                   |value 'displayed')|
                   |                  |
                   |'Deleted without  |
                   |being read' (used |
                   |for disposition-  |
                   |types 'deleted',  |
                   |'denied' and      |
                   |'failed' when     |
                   |action-mode is    |
                   |'automatic-       |
                   |action')          |
-------------------|------------------|--------------------------------
Status Text        |                  |Text in first part (human-
                   |                  |readable part)
===================|==================|================================


2.1.5 Message Delivery

    Within Internet mail, when ESMTP is used and delivery reports are
    requested [DSN-SMTP], delivery is considered to be acceptance of a
    message by the final server, that is, the server closest to the
    recipient.  When an MMS Relay/Server receives a message using ESMTP
    and a delivery report is requested, the MMS Relay/Server MAY
    consider the message delivered when it has been sent to the MMS User
    Agent.


3 Security Considerations

    Data contained within messages should not be automatically trusted.
    Even within a carrier's network, and certainly within the Internet,
    various deliberate and accidental attacks or corruptions are
    possible.  For example, routers may contain vulnerabilities which
    may be exploited, IP traffic may be intercepted and/or modified,
    etc.





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    The following messaging-related security threats can be identified:

    * Misidentification of message source.

    * Message interception (unauthorized disclosure of contents).

    * Unauthorized disclosure of message sender or recipient.

    * Message modification (by adversary).

    * Message replay.

    * Traffic analysis (determining who is communicating with whom).

    There are existing mechanisms used to protect email traffic against
    some of these threats, such as:

    * Use of SSL/TLS (via [StartTLS]) to address disclosure and
    modification in transit between adjacent servers.

    * SMTP Authentication [Auth] to protect against misidentification of
    message source.

    * Use of end-to-end security mechanisms such as [PGP] or S/MIME
    [SMIME] to protect message contents.

    * Use of [IPSec] to protect against disclosure or modification in
    transit between servers.

    These mechanisms SHOULD be employed whenever the required
    infrastructure is available, e.g., a certificate infrastructure is
    necessary to support S/MIME, or user agent support for PGP is
    available.  Enabling SMTP Authentication [Auth] and STARTTLS
    [StartTLS] are easy measures to deploy and SHOULD be used.

    Since MMS does not include a clear separation between in-transit
    envelope and message content, there are increased risks of
    unauthorized disclosure of information, and additional challenges in
    protecting data.  For example, Bcc recipients do not normally appear
    in the message content, only in the envelope; care MUST be taken in
    the gateway function to ensure that Bcc recipients which do appear
    are deleted from the message content.

    Some MMS features contain inherently more risk than others.  For
    example, reply charging and sender address hiding.  The reply
    charging mechanism requires a high degree of trust between entities
    with little technical basis.  Deliberate or accidental abuse of this
    trust can result in unexpected or unauthorized charges.  For
    example, a sender may be charged for unauthorized replies, or a


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    sender may be charged for a reply which the author thought would be
    paid for by the recipient.  A sender's identity may be disclosed in
    violation of a request for this to be blocked.  The identity of
    recipients may be disclosed to other recipients (or even
    non-recipients) for a message in which the sender intended for the
    recipients not to be disclosed.

    It is possible to hide the sender's identity from non-recipients
    using anonymous remailers.  It is hard to hide the sender's identity
    from recipients when the mail is cryptographically signed.  In view
    of anti-spam measures it may be undesirable to hide the sender's
    identity.

    Additional mechanisms can be developed to protect against various
    threats, however, these are not included in this version of this
    specification.  It is strongly RECOMMENDED that features such as
    reply charging and sender identity hiding not be used across carrier
    domains, and be used within carrier domains only with full
    understanding of the risks involved.


4 Normative References


    IETF:

    [DSN-Msg] "An Extensible Message Format for Delivery Status
    Notifications", Moore, Vaudreuil, RFC 3464, January 2003.

    [DSN-SMTP] "SMTP Service Extension for Delivery Status
    Notifications", Moore, RFC 3461, January 2003.

    [Hdr-Enc] "MIME (Multipurpose Internet Mail Extensions) Part Three:
    Message Header Extensions for Non-ASCII Text", Moore, RFC 2047,
    November 1996.

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

    [MDN] "An Extensible Message Format for Message Disposition
    Notifications", Fajman, RFC 2298, March 1998.

    [Msg-Fmt] ÓInternet Message FormatÔ, Resnick, RFC 2822, April 2001.

    [Report-Fmt] ÓThe Multipart/Report Content Type for the Reporting of
    Mail System Administrative MessagesÔ, Vaudreuil, RFC 3462, January
    2003




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    [RESP] Enhanced Mail System Status Codes, Vaudreuil, RFC 1893,
    January 1996.

    [SMTP] ÓSimple Mail Transfer ProtocolÔ, Klensin, RFC 2821, April
    2001.


5 Informative References

    IETF:

    [Auth] "SMTP Service Extension for Authentication", Myers, RFC 2554,
    March 1999

    [BINARY] SMTP Service Extensions for Transmission of Large and
    Binary MIME Messages", Vaudreuil, Parsons, RFC 3030, December 2000.

    [Codes] "SMTP Service Extension for Returning Enhanced Error Codes",
    Freed, RFC 2034, October 1996.

    [Deliver-By] "Deliver By SMTP Service Extension", Newman, RFC 2852,
    June 2000.

    [Msg-Encap] "Proposed Standard for Message Encapsulation", Rose,
    Stefferud, RFC 934, January 1985.

    [Hdrs] "Common Internet Message Headers", J. Palme, RFC 2076,
    February 1997.

    [IPSec] "Security Architecture for the Internet Protocol", Kent,
    Atkinson, RFC 2401, November 1998

    [PGP] "MIME Security with OpenPGP", Elkins, Del Torto, Levien,
    Roessler, RFC 3156, August 2001

    [SMIME] "S/MIME Version 3 Message Specification", Ramsdell, RFC
    2633, June 1999

    [StartTLS] "SMTP Service Extension for Secure SMTP over Transport
    Layer Security", Hoffman, RFC 3207, February 2002

    [Submission] ÓMessage SubmissionÔ, Gellens, Klensin, RFC 2476,
    December 1998.

    [VPIM] ÓVoice Profile Internet Mail Ï- Version 2Ô, Vaudreuil,
    Parsons, RFC 2421, September 1998.





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    OMA:

        OMA specifications are available at the OMA web site
        <http://www.openmobilealliance.org>.

    [OMA-MMS] OMA-WAP-MMS-ENC-V1_2-20040323-C

    3GPP2 and 3GPP:

        3GPP2 specifications are available at the 3GPP2 (Third
        Generation Partnership Project 2) web site
        <http://www.3gpp2.org>.

        3GPP specifications are available at the 3GPP (Third Generation
        Partnership Project) web site <http://www.3gpp.org>

    [Stage_3] "MMS MM1 Stage 3 using OMA/WAP", X.S0016-310

    "MMS MM4 Stage 3 Inter-Carrier Interworking", X.S0016-340

    ÓMultimedia Messaging Service:  Functional description; Stage 2Ô, TS
    23.140 Release 5.

    [Formats] "Multimedia Messaging Service (MMS) Media Format and
    Codecs for cdma2000 Spread Spectrum SystemsÔ, C.S0045

    [Overview] "Multimedia Messaging Services (MMS) Overview",
    X.S0016-000

    [Stage_1] "Multimedia Messaging Services (MMS); Stage 1",
    Requirements, October 2002, S.R0064-0.

    [Stage_2] ÓMultimedia Messaging Service (MMS); Stage 2", Functional
    Specification, April 2003, X.S0016-200.

              "Multimedia Messaging Service; Media formats and codecs",
    TS26.140Release 5.


6 Author's Address

    Randall Gellens
    QUALCOMM Incorporated
    5775 Morehouse Drive
    San Diego, CA  92121
    USA
    randy@qualcomm.com




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