As per Relevance of the word permanent, we have this rfc below:
Network Working Group G.
Request for Comments: 1893 Octel Network
Category: Standards Track January 1996
Enhanced Mail System Status
Status of this
This document specifies an Internet standards track protocol for
Internet community, and requests discussion and suggestions
improvements. Please refer to the current edition of the "
Official Protocol Standards" (STD 1) for the standardization
and status of this protocol. Distribution of this memo is unlimited
1.
There currently is not a standard mechanism for the reporting of
system errors except for the limited set offered by SMTP and
system specific text descriptions sent in mail messages. There is
pressing need for a rich machine readable status code for use
delivery status notifications [DSN]. This document proposes a
set of status codes for this purpose
SMTP [SMTP] error codes have historically been used for
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.
majority of the codes are protocol specific response codes such
the 354 response to the SMTP data command. Each of the 12
codes are each overloaded to indicate several error conditions each
SMTP suffers some scars from history, most notably the
damage to the reply code extension mechanism by uncontrolled use
This proposal facilitates future extensibility by requiring
client to interpret unknown error codes according to the theory
codes while requiring servers to register new response codes
The SMTP theory of reply codes partitioned in the number space such
manner that the remaining available codes will not provide the
needed. The most critical example is the existence of only 5
remaining codes for mail system errors. The mail
classification includes both host and mailbox error conditions.
remaining third digit space would be completely consumed as needed
indicate MIME and media conversion errors and security system errors
A revision to the SMTP theory of reply codes to better distribute
error conditions in the number space will necessarily be
with SMTP. Further, consumption of the remaining reply-code
Vaudreuil Standards Track [Page 1]
RFC 1893 Mail System Status Codes January 1996
space for delivery notification reporting will reduce the
codes for new ESMTP extensions
The following proposal is based on the SMTP theory of reply codes
It adopts the success, permanent error, and transient error
of the first value, with a further description and classification
the second. This proposal re-distributes the classifications
better distribute the error conditions, such as separating
from host errors
2. Status
This document defines a new set of status codes to report mail
conditions. These status codes are intended to be used for media
language independent status reporting. They are not intended
system specific diagnostics
The syntax of the new status codes is defined as
status-code = class "." subject "."
class = "2"/"4"/"5"
subject = 1*3
detail = 1*3
White-space characters and comments are NOT allowed within a status
code. Each numeric sub-code within the status-code MUST be
without leading zero digits
Status codes consist of three numerical fields separated by ".".
first sub-code indicates whether the delivery attempt was successful
The second sub-code indicates the probable source of any
anomalies, and the third sub-code indicates a precise
condition
The codes space defined is intended to be extensible only
standards track documents. Mail system specific status codes
be mapped as close as possible to the standard status codes.
should send only defined, registered status codes. System
errors and diagnostics should be carried by means other than
codes
New subject and detail codes will be added over time. Because
number space is large, it is not intended that published status
will ever be redefined or eliminated. Clients should preserve
extensibility of the code space by reporting the general
described in the subject sub-code when the specific detail
unrecognized
Vaudreuil Standards Track [Page 2]
RFC 1893 Mail System Status Codes January 1996
The class sub-code provides a broad classification of the status
The enumerated values the class are defined as
2.X.X
Success specifies that the DSN is reporting a positive
action. Detail sub-codes may provide notification
transformations required for delivery
4.X.X Persistent Transient
A persistent transient failure is one in which the message
sent is valid, but some temporary event prevents the
sending of the message. Sending in the future may be successful
5.X.X Permanent
A permanent failure is one which is not likely to be resolved
resending the message in the current form. Some change to
message or the destination must be made for successful delivery
A client must recognize and report class sub-code even
subsequent subject sub-codes are unrecognized
The subject sub-code classifies the status. This value applies
each of the three classifications. The subject sub-code,
recognized, must be reported even if the additional detail
by the detail sub-code is not recognized. The enumerated values
the subject sub-code are
X.0.X Other or Undefined
There is no additional subject information available
X.1.X Addressing
The address status reports on the originator or
address. It may include address syntax or validity.
errors can generally be corrected by the sender and retried
X.2.X Mailbox
Mailbox status indicates that something having to do with
mailbox has cause this DSN. Mailbox issues are assumed to
under the general control of the recipient
Vaudreuil Standards Track [Page 3]
RFC 1893 Mail System Status Codes January 1996
X.3.X Mail System
Mail system status indicates that something having to
with the destination system has caused this DSN.
issues are assumed to be under the general control of
destination system administrator
X.4.X Network and Routing
The networking or routing codes report status about
delivery system itself. These system components include
necessary infrastructure such as directory and
services. Network issues are assumed to be under
control of the destination or intermediate
administrator
X.5.X Mail Delivery Protocol
The mail delivery protocol status codes report
involving the message delivery protocol. These
include the full range of problems resulting
implementation errors or an unreliable connection.
delivery protocol issues may be controlled by many
including the originating system, destination system,
intermediate system administrators
X.6.X Message Content or Media
The message content or media status codes report
involving the content of the message. These codes
failures due to translation, transcoding, or
unsupported message media. Message content or media
are under the control of both the sender and the receiver
both of whom must support a common set of
content-types
X.7.X Security or Policy
The security or policy status codes report
involving policies such as per-recipient or per-
filtering and cryptographic operations. Security and
status issues are assumed to be under the control of
or both the sender and recipient. Both the sender
recipient must permit the exchange of messages and
the exchange of necessary keys and certificates
cryptographic operations
Vaudreuil Standards Track [Page 4]
RFC 1893 Mail System Status Codes January 1996
3. Enumerated Status
The following section defines and describes the detail sub-code.
detail value provides more information about the status and
defined relative to the subject of the status
3.1 Other or Undefined
X.0.0 Other undefined
Other undefined status is the only undefined error code.
should be used for all errors for which only the class of
error is known
3.2 Address
X.1.0 Other address
Something about the address specified in the message
this DSN
X.1.1 Bad destination mailbox
The mailbox specified in the address does not exist.
Internet mail names, this means the address portion to
left of the "@" sign is invalid. This code is only
for permanent failures
X.1.2 Bad destination system
The destination system specified in the address does
exist or is incapable of accepting mail. For Internet
names, this means the address portion to the right of
"@" is invalid for mail. This codes is only useful
permanent failures
X.1.3 Bad destination mailbox address
The destination address was syntactically invalid. This
apply to any field in the address. This code is only
for permanent failures
X.1.4 Destination mailbox address
The mailbox address as specified matches one or
recipients on the destination system. This may result if
heuristic address mapping algorithm is used to map
specified address to a local mailbox name
Vaudreuil Standards Track [Page 5]
RFC 1893 Mail System Status Codes January 1996
X.1.5 Destination address
This mailbox address as specified was valid. This
code should be used for positive delivery reports
X.1.6 Destination mailbox has moved, No forwarding
The mailbox address provided was at one time valid, but
is no longer being accepted for that address. This code
only useful for permanent failures
X.1.7 Bad sender's mailbox address
The sender's address was syntactically invalid. This
apply to any field in the address
X.1.8 Bad sender's system
The sender's system specified in the address does not
or is incapable of accepting return mail. For domain names
this means the address portion to the right of the "@"
invalid for mail
3.3 Mailbox
X.2.0 Other or undefined mailbox
The mailbox exists, but something about the
mailbox has caused the sending of this DSN
X.2.1 Mailbox disabled, not accepting
The mailbox exists, but is not accepting messages. This
be a permanent error if the mailbox will never be re-
or a transient error if the mailbox is only
disabled
X.2.2 Mailbox
The mailbox is full because the user has exceeded
per-mailbox administrative quota or physical capacity.
general semantics implies that the recipient can
messages to make more space available. This code should
used as a persistent transient failure
Vaudreuil Standards Track [Page 6]
RFC 1893 Mail System Status Codes January 1996
X.2.3 Message length exceeds administrative
A per-mailbox administrative message length limit has
exceeded. This status code should be used when
per-mailbox message length limit is less than the
system limit. This code should be used as a
failure
X.2.4 Mailing list expansion
The mailbox is a mailing list address and the mailing
was unable to be expanded. This code may represent
permanent failure or a persistent transient failure
3.4 Mail system
X.3.0 Other or undefined mail system
The destination system exists and normally accepts mail,
something about the system has caused the generation of
DSN
X.3.1 Mail system
Mail system storage has been exceeded. The
semantics imply that the individual recipient may not
able to delete material to make room for
messages. This is useful only as a persistent
error
X.3.2 System not accepting network
The host on which the mailbox is resident is not
messages. Examples of such conditions include an
shutdown, excessive load, or system maintenance. This
useful for both permanent and permanent transient errors
X.3.3 System not capable of selected
Selected features specified for the message are
supported by the destination system. This can occur
gateways when features from one domain cannot be mapped
the supported feature in another
Vaudreuil Standards Track [Page 7]
RFC 1893 Mail System Status Codes January 1996
X.3.4 Message too big for
The message is larger than per-message size limit.
limit may either be for physical or administrative reasons
This is useful only as a permanent error
X.3.5 System incorrectly
The system is not configured in a manner which will
it to accept this message
3.5 Network and Routing
X.4.0 Other or undefined network or routing
Something went wrong with the networking, but it is
clear what the problem is, or the problem cannot be
expressed with any of the other provided detail codes
X.4.1 No answer from
The outbound connection attempt was not answered,
because the remote system was busy, or otherwise unable
take a call. This is useful only as a persistent
error
X.4.2 Bad
The outbound connection was established, but was
unable to complete the message transaction, either
of time-out, or inadequate connection quality. This
useful only as a persistent transient error
X.4.3 Directory server
The network system was unable to forward the message
because a directory server was unavailable. This is
only as a persistent transient error
The inability to connect to an Internet DNS server is
example of the directory server failure error
X.4.4 Unable to
The mail system was unable to determine the next hop for
message because the necessary routing information
unavailable from the directory server. This is useful
both permanent and persistent transient errors
Vaudreuil Standards Track [Page 8]
RFC 1893 Mail System Status Codes January 1996
A DNS lookup returning only an SOA (Start of Administration
record for a domain name is one example of the unable
route error
X.4.5 Mail system
The mail system was unable to deliver the message
the mail system was congested. This is useful only as
persistent transient error
X.4.6 Routing loop
A routing loop caused the message to be forwarded too
times, either because of incorrect routing tables or a
forwarding loop. This is useful only as a
transient error
X.4.7 Delivery time
The message was considered too old by the rejecting system
either because it remained on that host too long or
the time-to-live value specified by the sender of
message was exceeded. If possible, the code for the
problem found when delivery was attempted should be
rather than this code. This is useful only as a
transient error
3.6 Mail Delivery Protocol
X.5.0 Other or undefined protocol
Something was wrong with the protocol necessary to
the message to the next hop and the problem cannot be
expressed with any of the other provided detail codes
X.5.1 Invalid
A mail transaction protocol command was issued which
either out of sequence or unsupported. This is useful
as a permanent error
X.5.2 Syntax
A mail transaction protocol command was issued which
not be interpreted, either because the syntax was wrong
the command is unrecognized. This is useful only as
permanent error
Vaudreuil Standards Track [Page 9]
RFC 1893 Mail System Status Codes January 1996
X.5.3 Too many
More recipients were specified for the message than
have been delivered by the protocol. This error
normally result in the segmentation of the message into two
the remainder of the recipients to be delivered on
subsequent delivery attempt. It is included in this list
the event that such segmentation is not possible
X.5.4 Invalid command
A valid mail transaction protocol command was issued
invalid arguments, either because the arguments were out
range or represented unrecognized features. This is
only as a permanent error
X.5.5 Wrong protocol
A protocol version mis-match existed which could not
automatically resolved by the communicating parties
3.7 Message Content or Message Media
X.6.0 Other or undefined media
Something about the content of a message caused it to
considered undeliverable and the problem cannot be
expressed with any of the other provided detail codes
X.6.1 Media not
The media of the message is not supported by either
delivery protocol or the next system in the forwarding path
This is useful only as a permanent error
X.6.2 Conversion required and
The content of the message must be converted before it
be delivered and such conversion is not permitted.
prohibitions may be the expression of the sender in
message itself or the policy of the sending host
X.6.3 Conversion required but not
The message content must be converted to be forwarded
such conversion is not possible or is not practical by
host in the forwarding path. This condition may result
an ESMTP gateway supports 8bit transport but is not able
Vaudreuil Standards Track [Page 10]
RFC 1893 Mail System Status Codes January 1996
downgrade the message to 7 bit as required for the next hop
X.6.4 Conversion with loss
This is a warning sent to the sender when message
was successfully but when the delivery required a
in which some data was lost. This may also be a
error if the sender has indicated that conversion with
is prohibited for the message
X.6.5 Conversion
A conversion was required but was unsuccessful. This may
useful as a permanent or persistent temporary notification
3.8 Security or Policy
X.7.0 Other or undefined security
Something related to security caused the message to
returned, and the problem cannot be well expressed with
of the other provided detail codes. This status code
also be used when the condition cannot be further
because of security policies in force
X.7.1 Delivery not authorized, message
The sender is not authorized to send to the destination
This can be the result of per-host or per-
filtering. This memo does not discuss the merits of
such filtering, but provides a mechanism to report such
This is useful only as a permanent error
X.7.2 Mailing list expansion
The sender is not authorized to send a message to
intended mailing list. This is useful only as a
error
X.7.3 Security conversion required but not
A conversion from one secure messaging protocol to
was required for delivery and such conversion was
possible. This is useful only as a permanent error
Vaudreuil Standards Track [Page 11]
RFC 1893 Mail System Status Codes January 1996
X.7.4 Security features not
A message contained security features such as
authentication which could not be supported on the
protocol. This is useful only as a permanent error
X.7.5 Cryptographic
A transport system otherwise authorized to validate
decrypt a message in transport was unable to do so
necessary information such as key was not available or
information was invalid
X.7.6 Cryptographic algorithm not
A transport system otherwise authorized to validate
decrypt a message was unable to do so because the
algorithm was not supported
X.7.7 Message integrity
A transport system otherwise authorized to validate
message was unable to do so because the message
corrupted or altered. This may be useful as a permanent
transient persistent, or successful delivery code
4.
[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
Delivery Status Notifications", RFC 1894, University
Tennessee, Octel Network Services, January 1996.
5. Security
This document describes a status code system with
precision. Use of these status codes may disclose
information about how an internal mail system is implemented
that currently available
6.
The author wishes to offer special thanks to Harald Alvestrand,
Kaittola, and Keith Moore for their extensive review and
suggestions
Vaudreuil Standards Track [Page 12]
RFC 1893 Mail System Status Codes January 1996
7. Author's
Gregory M.
Octel Network
17060 Dallas
Suite 214
Dallas, TX 75248-1905
Voice/Fax: +1-214-733-2722
EMail: Greg.Vaudreuil@Octel.
Vaudreuil Standards Track [Page 13]
RFC 1893 Mail System Status Codes January 1996
8. Appendix - Collected Status
X.1.0 Other address
X.1.1 Bad destination mailbox
X.1.2 Bad destination system
X.1.3 Bad destination mailbox address
X.1.4 Destination mailbox address
X.1.5 Destination mailbox address
X.1.6 Mailbox has
X.1.7 Bad sender's mailbox address
X.1.8 Bad sender's system
X.2.0 Other or undefined mailbox
X.2.1 Mailbox disabled, not accepting
X.2.2 Mailbox
X.2.3 Message length exceeds administrative limit
X.2.4 Mailing list expansion
X.3.0 Other or undefined mail system
X.3.1 Mail system
X.3.2 System not accepting network
X.3.3 System not capable of selected
X.3.4 Message too big for
X.4.0 Other or undefined network or routing
X.4.1 No answer from
X.4.2 Bad
X.4.3 Routing server
X.4.4 Unable to
X.4.5 Network
X.4.6 Routing loop
X.4.7 Delivery time
X.5.0 Other or undefined protocol
X.5.1 Invalid
X.5.2 Syntax
X.5.3 Too many
X.5.4 Invalid command
X.5.5 Wrong protocol
X.6.0 Other or undefined media
X.6.1 Media not
X.6.2 Conversion required and
X.6.3 Conversion required but not
X.6.4 Conversion with loss
X.6.5 Conversion
Vaudreuil Standards Track [Page 14]
RFC 1893 Mail System Status Codes January 1996
X.7.0 Other or undefined security
X.7.1 Delivery not authorized, message
X.7.2 Mailing list expansion
X.7.3 Security conversion required but not
X.7.4 Security features not
X.7.5 Cryptographic
X.7.6 Cryptographic algorithm not
X.7.7 Message integrity
Vaudreuil Standards Track [Page 15]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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