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Enhanced Mail System Status Codes (RFC1893) Disclosure Number: IPCOM000004148D
Original Publication Date: 1996-Jan-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 18 page(s) / 26K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Vaudreuil: AUTHOR


Status of this Memo

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 11% of the total text.

Network Working Group G. Vaudreuil

Request for Comments: 1893 Octel Network Services

Category: Standards Track January 1996

Enhanced Mail System Status Codes

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

1. Overview

There currently is not a standard mechanism for the reporting of mail

system errors except for 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 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 each 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 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