RFC 1893 (rfc1893) - Page 2 of 15
Enhanced Mail System Status Codes
Alternative Format: Original Text Document
RFC 1893 Mail System Status Codes January 1996
space for delivery notification reporting will reduce the available
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 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.
2. Status Codes
This document defines a new set of status codes to report mail system
conditions. These status codes are intended to be 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.
The codes 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.
Vaudreuil Standards Track