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Versions: (RFC 1893) 00 01 02 RFC 3463

     Internet Draft                                       Greg Vaudreuil
     Obsoletes: RFC 1893                             Lucent Technologies
     Expires in six months                                August 8, 2002
  
  
                       Enhanced Mail System Status Codes
  
                        <draft-vaudreuil-1893bis-02.txt>
  
  
  
  Status of this Memo
  
     This document is an Internet-Draft and is in full conformance with all
     provisions of Section 10 of RFC 2026.
  
     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 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 a "work in progress".
  
     The list of current Internet-Drafts can be accessed at
     http://www.ietf.org/1id-abstracts.html
  
     The list of Internet-Draft Shadow Directories can be accessed at
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  Copyright Notice
  
     Copyright (C) The Internet Society (2002).  All Rights Reserved.
  
     This Internet-Draft is in conformance with Section 10 of RFC 2026.
  
  Abstract
  
     This document defines a set of extended status codes for use within
     the mail system for delivery status reports, tracking, and improved
     diagnostics.  The in combination with other information provided in
     the DSN delivery report, these codes facilitate media and language
     independent rendering of message delivery status.
  
  
  

  
  
     Internet Draft      Mail System Status Codes         August 8, 2002
  
  
  Working Group Summary
  
     RFC 1893 was a product of the Notary working group.  This document is
     a revision of that document providing clarifications as necessary to
     advance to draft standard.
  
  Document Conventions
  
     The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
     "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
     document are to be interpreted as described in RFC-2119 [RFC2119].
  
  Table of Contents
  
  1.   OVERVIEW ..........................................................3
  2.   STATUS CODE STRUCTURE .............................................4
  3.   ENUMERATED STATUS CODES ...........................................7
    3.1  Other or Undefined Status .......................................7
    3.2  Address Status ..................................................7
    3.3  Mailbox Status ..................................................8
    3.4  Mail system status ..............................................9
    3.5  Network and Routing Status .....................................10
    3.6  Mail Delivery Protocol Status ..................................11
    3.7  Message Content or Message Media Status ........................12
    3.8  Security or Policy Status ......................................13
  4.   REFERENCES .......................................................15
  5.   SECURITY CONSIDERATIONS ..........................................15
  6.   COPYRIGHT NOTICE .................................................16
  7.   AUTHOR'S ADDRESS .................................................16
  8.   APPENDIX A - CHANGES FROM RFC1893 ................................17
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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     Internet Draft      Mail System Status Codes         August 8, 2002
  
  
  1. Overview
  
     There is a need for a standard mechanism for the reporting of mail
     system errors richer than the limited set offered by SMTP and the
     system specific text descriptions sent in mail messages.  There is a
     pressing need for a rich machine-readable, human language independent
     status code for use in delivery status notifications [DSN].  This
     document proposes a new set of status codes for this purpose.
  
     SMTP [SMTP] error codes have historically been used for reporting mail
     system errors.  Because of limitations in the SMTP code design, these
     are not suitable for use in delivery status notifications. SMTP
     provides about 12 useful codes for delivery reports.  The majority of
     the codes are protocol specific response codes such as the 354
     response to the SMTP data command.  Each of the 12 useful codes are
     overloaded to indicate several error conditions each. SMTP suffers
     some scars from history, most notably the unfortunate damage to the
     reply code extension mechanism by uncontrolled use. This proposal
     facilitates future extensibility by requiring the client to interpret
     unknown error codes according to the theory of codes while requiring
     servers to register new response codes.
  
     The SMTP theory of reply codes partitioned in the number space such a
     manner that the remaining available codes will not provide the space
     needed.  The most critical example is the existence of only 5
     remaining codes for mail system errors.  The mail system
     classification includes both host and mailbox error conditions.  The
     remaining third digit space would be completely consumed as needed to
     indicate MIME and media conversion errors and security system errors.
  
     A revision to the SMTP theory of reply codes to better distribute the
     error conditions in the number space will necessarily be incompatible
     with SMTP.  Further, consumption of the remaining reply-code number
     space for delivery notification reporting will reduce the available
     codes for new ESMTP extensions.
  
     The following status code set is based on the SMTP theory of reply
     codes. It adopts the success, permanent error, and transient error
     semantics of the first value, with a further description and
     classification in the second.  This proposal re-distributes the
     classifications to better distribute the error conditions, such as
     separating mailbox from host errors.
  
  
  
  
  
  
  
  
  
  
  
  
  
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     Internet Draft      Mail System Status Codes         August 8, 2002
  
  
  2. Status Code Structure
  
     This document defines a new set of status codes to report mail system
     conditions.  These status codes are used for media and language
     independent status reporting.  They are not intended for system
     specific diagnostics.
  
     The syntax of the new status codes is defined as:
  
      status-code = class "." subject "." detail
  
      class = "2"/"4"/"5"
  
      subject = 1*3digit
  
      detail = 1*3digit
  
     White-space characters and comments are NOT allowed within a status-
     code.  Each numeric sub-code within the status-code MUST be expressed
     without leading zero digits.
  
     Status codes consist of three numerical fields separated by ".". The
     first sub-code indicates whether the delivery attempt was successful.
     The second sub-code indicates the probable source of any delivery
     anomalies, and the third sub-code indicates a precise error condition.
  
     Example:  2.1.23
  
     The code space defined is intended to be extensible only by standards
     track documents.  Mail system specific status codes should be mapped
     as close as possible to the standard status codes.  Servers should
     send only defined, registered status codes.  System specific errors
     and diagnostics should be carried by means other than status codes.
  
     New subject and detail codes will be added over time.  Because the
     number space is large, it is not intended that published status codes
     will ever be redefined or eliminated.  Clients should preserve the
     extensibility of the code space by reporting the general error
     described in the subject sub-code when the specific detail is
     unrecognized.
  
     The class sub-code provides a broad classification of the status. The
     enumerated values for each class are defined as:
  
       2.XXX.XXX   Success
  
                 Success specifies that the DSN is reporting a positive
                 delivery action.  Detail sub-codes may provide
                 notification of transformations required for delivery.
  
       4.XXX.XXX   Persistent Transient Failure
  
                 A persistent transient failure is one in which the
                 message as sent is valid, but some temporary event
  
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                 prevents the successful sending of the message.  Sending
                 in the future may be successful.
  
       5.XXX.XXX   Permanent Failure
  
                 A permanent failure is one which is not likely to be
                 resolved by resending the message in the current form.
                 Some change to the message or the destination must be
                 made for successful delivery.
  
     A client must recognize and report class sub-code even where
     subsequent subject sub-codes are unrecognized.
  
     The subject sub-code classifies the status.  This value applies to
     each of the three classifications.  The subject sub-code, if
     recognized, must be reported even if the additional detail provided by
     the detail sub-code is not recognized.  The enumerated values for the
     subject sub-code are:
  
          X.0.XXX   Other or Undefined Status
  
                 There is no additional subject information available.
  
          X.1.XXX Addressing Status
  
                 The address status reports on the originator or
                 destination address.  It may include address syntax or
                 validity.  These errors can generally be corrected by the
                 sender and retried.
  
          X.2.XXX Mailbox Status
  
                 Mailbox status indicates that something having to do with
                 the mailbox has caused this DSN.  Mailbox issues are
                 assumed to be under the general control of the recipient.
  
          X.3.XXX Mail System Status
  
                 Mail system status indicates that something having to do
                 with the destination system has caused this DSN.  System
                 issues are assumed to be under the general control of the
                 destination system administrator.
  
          X.4.XXX Network and Routing Status
  
                 The networking or routing codes report status about the
                 delivery system itself.  These system components include
                 any necessary infrastructure such as directory and
                 routing services.  Network issues are assumed to be under
                 the control of the destination or intermediate system
                 administrator.
  
          X.5.XXX Mail Delivery Protocol Status
  
  
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                 The mail delivery protocol status codes report failures
                 involving the message delivery protocol.  These failures
                 include the full range of problems resulting from
                 implementation errors or an unreliable connection.
  
          X.6.XXX Message Content or Media Status
  
                 The message content or media status codes report failures
                 involving the content of the message.  These codes report
                 failures due to translation, transcoding, or otherwise
                 unsupported message media.  Message content or media
                 issues are under the control of both the sender and the
                 receiver, both of which must support a common set of
                 supported content-types.
  
          X.7.XXX Security or Policy Status
  
                 The security or policy status codes report failures
                 involving policies such as per-recipient or per-host
                 filtering and cryptographic operations.  Security and
                 policy status issues are assumed to be under the control
                 of either or both the sender and recipient.  Both the
                 sender and recipient must permit the exchange of messages
                 and arrange the exchange of necessary keys and
                 certificates for cryptographic operations.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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  3. Enumerated Status Codes
  
     The following section defines and describes the detail sub-code. The
     detail value provides more information about the status and is defined
     relative to the subject of the status.
  
  3.1 Other or Undefined Status
  
          X.0.0   Other undefined Status
  
                 Other undefined status is the only undefined error code.
                 It should be used for all errors for which only the class
                 of the error is known.
  
  3.2 Address Status
  
          X.1.0   Other address status
  
                 Something about the address specified in the message
                 caused this DSN.
  
          X.1.1   Bad destination mailbox address
  
                 The mailbox specified in the address does not exist.  For
                 Internet mail names, this means the address portion to
                 the left of the "@" sign is invalid.  This code is only
                 useful for permanent failures.
  
          X.1.2   Bad destination system address
  
                 The destination system specified in the address does not
                 exist or is incapable of accepting mail.  For Internet
                 mail names, this means the address portion to the right
                 of the "@" is invalid for mail.  This codes is only
                 useful for permanent failures.
  
          X.1.3   Bad destination mailbox address syntax
  
                 The destination address was syntactically invalid.  This
                 can apply to any field in the address.  This code is only
                 useful for permanent failures.
  
          X.1.4   Destination mailbox address ambiguous
  
                 The mailbox address as specified matches one or more
                 recipients on the destination system.  This may result if
                 a heuristic address mapping algorithm is used to map the
                 specified address to a local mailbox name.
  
          X.1.5   Destination address valid
  
                 This mailbox address as specified was valid.  This status
                 code should be used for positive delivery reports.
  
  
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          X.1.6   Destination mailbox has moved, No forwarding address
  
                 The mailbox address provided was at one time valid, but
                 mail is no longer being accepted for that address.  This
                 code is only useful for permanent failures.
  
          X.1.7   Bad sender's mailbox address syntax
  
                 The sender's address was syntactically invalid.  This can
                 apply to any field in the address.
  
          X.1.8   Bad sender's system address
  
                 The sender's system specified in the address does not
                 exist or is incapable of accepting return mail.  For
                 domain names, this means the address portion to the right
                 of the "@" is invalid for mail.
  
  3.3 Mailbox Status
  
          X.2.0   Other or undefined mailbox status
  
                 The mailbox exists, but something about the destination
                 mailbox has caused the sending of this DSN.
  
          X.2.1   Mailbox disabled, not accepting messages
  
                 The mailbox exists, but is not accepting messages.  This
                 may be a permanent error if the mailbox will never be re-
                 enabled or a transient error if the mailbox is only
                 temporarily disabled.
  
          X.2.2   Mailbox full
  
                 The mailbox is full because the user has exceeded a per-
                 mailbox administrative quota or physical capacity.  The
                 general semantics implies that the recipient can delete
                 messages to make more space available.  This code should
                 be used as a persistent transient failure.
  
          X.2.3   Message length exceeds administrative limit
  
                 A per-mailbox administrative message length limit has
                 been exceeded.  This status code should be used when the
                 per-mailbox message length limit is less than the general
                 system limit.  This code should be used as a permanent
                 failure.
  
          X.2.4   Mailing list expansion problem
  
                 The mailbox is a mailing list address and the mailing
                 list was unable to be expanded.  This code may represent
                 a permanent failure or a persistent transient failure.
  
  
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  3.4  Mail system status
  
         X.3.0   Other or undefined mail system status
  
                 The destination system exists and normally accepts mail,
                 but something about the system has caused the generation
                 of this DSN.
  
          X.3.1   Mail system full
  
                 Mail system storage has been exceeded.  The general
                 semantics imply that the individual recipient may not be
                 able to delete material to make room for additional
                 messages.  This is useful only as a persistent transient
                 error.
  
          X.3.2   System not accepting network messages
  
                 The host on which the mailbox is resident is not
                 accepting messages.  Examples of such conditions include
                 an immanent shutdown, excessive load, or system
                 maintenance.  This is useful for both permanent and
                 permanent transient errors.
  
          X.3.3   System not capable of selected features
  
                 Selected features specified for the message are not
                 supported by the destination system.  This can occur in
                 gateways when features from one domain cannot be mapped
                 onto the supported feature in another.
  
          X.3.4   Message too big for system
  
                 The message is larger than per-message size limit.  This
                 limit may either be for physical or administrative
                 reasons. This is useful only as a permanent error.
  
          X.3.5 System incorrectly configured
  
                 The system is not configured in a manner that will permit
                 it to accept this message.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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  3.5 Network and Routing Status
  
          X.4.0   Other or undefined network or routing status
  
                 Something went wrong with the networking, but it is not
                 clear what the problem is, or the problem cannot be well
                 expressed with any of the other provided detail codes.
  
          X.4.1   No answer from host
  
                 The outbound connection attempt was not answered, either
                 because the remote system was busy, or otherwise unable
                 to take a call.  This is useful only as a persistent
                 transient error.
  
          X.4.2   Bad connection
  
                 The outbound connection was established, but was
                 otherwise unable to complete the message transaction,
                 either because of time-out, or inadequate connection
                 quality. This is useful only as a persistent transient
                 error.
  
          X.4.3   Directory server failure
  
                 The network system was unable to forward the message,
                 because a directory server was unavailable.  This is
                 useful only as a persistent transient error.
  
                 The inability to connect to an Internet DNS server is one
                 example of the directory server failure error.
  
          X.4.4   Unable to route
  
                 The mail system was unable to determine the next hop for
                 the message because the necessary routing information was
                 unavailable from the directory server. This is useful for
                 both permanent and persistent transient errors.
  
                 A DNS lookup returning only an SOA (Start of
                 Administration) record for a domain name is one example
                 of the unable to route error.
  
          X.4.5   Mail system congestion
  
                 The mail system was unable to deliver the message because
                 the mail system was congested. This is useful only as a
                 persistent transient error.
  
          X.4.6   Routing loop detected
  
                 A routing loop caused the message to be forwarded too
                 many times, either because of incorrect routing tables or
  
  
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                 a user-forwarding loop. This is useful only as a
                 persistent transient error.
  
          X.4.7   Delivery time expired
  
                 The message was considered too old by the rejecting
                 system, either because it remained on that host too long
                 or because the time-to-live value specified by the sender
                 of the message was exceeded. If possible, the code for
                 the actual problem found when delivery was attempted
                 should be returned rather than this code.  This is useful
                 only as a persistent transient error.
  
  3.6 Mail Delivery Protocol Status
  
          X.5.0   Other or undefined protocol status
  
                 Something was wrong with the protocol necessary to
                 deliver the message to the next hop and the problem
                 cannot be well expressed with any of the other provided
                 detail codes.
  
          X.5.1   Invalid command
  
                 A mail transaction protocol command was issued which was
                 either out of sequence or unsupported.  This is useful
                 only as a permanent error.
  
          X.5.2   Syntax error
  
                 A mail transaction protocol command was issued which
                 could not be interpreted, either because the syntax was
                 wrong or the command is unrecognized. This is useful only
                 as a permanent error.
  
          X.5.3   Too many recipients
  
                 More recipients were specified for the message than could
                 have been delivered by the protocol.  This error should
                 normally result in the segmentation of the message into
                 two, the remainder of the recipients to be delivered on a
                 subsequent delivery attempt.  It is included in this list
                 in the event that such segmentation is not possible.
  
  
  
  
  
  
  
  
  
  
  
  
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          X.5.4   Invalid command arguments
  
                 A valid mail transaction protocol command was issued with
                 invalid arguments, either because the arguments were out
                 of range or represented unrecognized features. This is
                 useful only as a permanent error.
  
          X.5.5   Wrong protocol version
  
                 A protocol version mis-match existed which could not be
                 automatically resolved by the communicating parties.
  
  3.7 Message Content or Message Media Status
  
          X.6.0   Other or undefined media error
  
                 Something about the content of a message caused it to be
                 considered undeliverable and the problem cannot be well
                 expressed with any of the other provided detail codes.
  
          X.6.1   Media not supported
  
                 The media of the message is not supported by either the
                 delivery protocol or the next system in the forwarding
                 path. This is useful only as a permanent error.
  
          X.6.2   Conversion required and prohibited
  
                 The content of the message must be converted before it
                 can be delivered and such conversion is not permitted.
                 Such prohibitions may be the expression of the sender in
                 the message itself or the policy of the sending host.
  
          X.6.3   Conversion required but not supported
  
                 The message content must be converted in order to be
                 forwarded but such conversion is not possible or is not
                 practical by a host in the forwarding path.  This
                 condition may result when an ESMTP gateway supports 8bit
                 transport but is not able to downgrade the message to 7
                 bit as required for the next hop.
  
          X.6.4   Conversion with loss performed
  
                 This is a warning sent to the sender when message
                 delivery was successfully but when the delivery required
                 a conversion in which some data was lost.  This may also
                 be a permanent error if the sender has indicated that
                 conversion with loss is prohibited for the message.
  
  
  
  
  
  
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          X.6.5   Conversion Failed
  
                 A conversion was required but was unsuccessful.  This may
                 be useful as a permanent or persistent temporary
                 notification.
  
  3.8 Security or Policy Status
  
          X.7.0   Other or undefined security status
  
                 Something related to security caused the message to be
                 returned, and the problem cannot be well expressed with
                 any of the other provided detail codes.  This status code
                 may also be used when the condition cannot be further
                 described because of security policies in force.
  
          X.7.1   Delivery not authorized, message refused
  
                 The sender is not authorized to send to the destination.
                 This can be the result of per-host or per-recipient
                 filtering.  This memo does not discuss the merits of any
                 such filtering, but provides a mechanism to report such.
                 This is useful only as a permanent error.
  
          X.7.2   Mailing list expansion prohibited
  
                 The sender is not authorized to send a message to the
                 intended mailing list. This is useful only as a permanent
                 error.
  
          X.7.3   Security conversion required but not possible
  
                 A conversion from one secure messaging protocol to
                 another was required for delivery and such conversion was
                 not possible. This is useful only as a permanent error.
  
          X.7.4   Security features not supported
  
                 A message contained security features such as secure
                 authentication that could not be supported on the
                 delivery protocol. This is useful only as a permanent
                 error.
  
          X.7.5   Cryptographic failure
  
                 A transport system otherwise authorized to validate or
                 decrypt a message in transport was unable to do so
                 because necessary information such as key was not
                 available or such information was invalid.
  
  
  
  
  
  
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          X.7.6   Cryptographic algorithm not supported
  
                 A transport system otherwise authorized to validate or
                 decrypt a message was unable to do so because the
                 necessary algorithm was not supported.
  
          X.7.7   Message integrity failure
  
                 A transport system otherwise authorized to validate a
                 message was unable to do so because the message was
                 corrupted or altered.  This may be useful as a permanent,
                 transient persistent, or successful delivery code.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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  4. Normative References
  
     [SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
     USC/Information Sciences Institute, August 1982.
  
     [DSN] Moore, K., and G. Vaudreuil, "An Extensible Message Format for
     Delivery Status Notifications", <draft-vaudreuil-1894bis-02.txt>,
     University of Tennessee, Lucent Technologies, Work-in-Progress.
  
  5. Security Considerations
  
     This document describes a status code system with increased precision.
     Use of these status codes may disclose additional information about
     how an internal mail system is implemented beyond that currently
     available.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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  6. Copyright Notice
  
     "Copyright (C) The Internet Society (2002). All Rights Reserved.
  
     This document and translations of it may be copied and furnished to
     others, and derivative works that comment on or otherwise explain it
     or assist in its implementation may be prepared, copied, published and
     distributed, in whole or in part, without restriction of any kind,
     provided that the above copyright notice and this paragraph are
     included on all such copies and derivative works.  However, this
     document itself may not be modified in any way, such as by removing
     the copyright notice or references to the Internet Society or other
     Internet organizations, except as needed for the purpose of developing
     Internet standards in which case the procedures for copyrights defined
     in the Internet Standards process MUST be followed, or as required to
     translate it into languages other than English.
  
     The limited permissions granted above are perpetual and will not be
     revoked by the Internet Society or its successors or assigns.
  
     This document and the information contained herein is provided on an
     "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
     TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
     NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN
     WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
     MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE."
  
  7. Author's Address
  
     Gregory M. Vaudreuil
     Lucent Technologies
     17080 Dallas Parkway
     Dallas, TX 75248-1905
     Voice/Fax: +1-972-733-2722
     GregV@ieee.org
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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  8. Appendix A - Collected Status Codes
  
            X.1.0     Other address status
            X.1.1     Bad destination mailbox address
            X.1.2     Bad destination system address
            X.1.3     Bad destination mailbox address syntax
            X.1.4     Destination mailbox address ambiguous
            X.1.5     Destination mailbox address valid
            X.1.6     Mailbox has moved
            X.1.7     Bad sender's mailbox address syntax
            X.1.8     Bad sender's system address
  
  
            X.2.0     Other or undefined mailbox status
            X.2.1     Mailbox disabled, not accepting messages
            X.2.2     Mailbox full
            X.2.3     Message length exceeds administrative limit.
            X.2.4     Mailing list expansion problem
  
  
            X.3.0     Other or undefined mail system status
            X.3.1     Mail system full
            X.3.2     System not accepting network messages
            X.3.3     System not capable of selected features
            X.3.4     Message too big for system
  
  
            X.4.0     Other or undefined network or routing status
            X.4.1     No answer from host
            X.4.2     Bad connection
            X.4.3     Routing server failure
            X.4.4     Unable to route
            X.4.5     Network congestion
            X.4.6     Routing loop detected
            X.4.7     Delivery time expired
  
  
            X.5.0     Other or undefined protocol status
            X.5.1     Invalid command
            X.5.2     Syntax error
            X.5.3     Too many recipients
            X.5.4     Invalid command arguments
            X.5.5     Wrong protocol version
  
  
            X.6.0     Other or undefined media error
            X.6.1     Media not supported
            X.6.2     Conversion required and prohibited
            X.6.3     Conversion required but not supported
            X.6.4     Conversion with loss performed
            X.6.5     Conversion failed
  
  
  
  
     Vaudreuil                Expires 2/8/03                   [Page 17]
  

     Internet Draft      Mail System Status Codes         August 8, 2002
  
  
  
  
            X.7.0     Other or undefined security status
            X.7.1     Delivery not authorized, message refused
            X.7.2     Mailing list expansion prohibited
            X.7.3     Security conversion required but not possible
            X.7.4     Security features not supported
            X.7.5     Cryptographic failure
            X.7.6     Cryptographic algorithm not supported
            X.7.7     Message integrity failure
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
     Vaudreuil                Expires 2/8/03                   [Page 18]
  

     Internet Draft      Mail System Status Codes         August 8, 2002
  
  
  
  
  
  
  9. Appendix B - Changes from RFC1893
  
     Changed Authors contact information
  
     Updated required standards boilerplate
  
     Edited the text to make it spell-checker and grammar checker compliant
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
     Vaudreuil                Expires 2/8/03                   [Page 19]
  

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