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SMTP Service Extension for Message Size Declaration (RFC1427)

IP.com Disclosure Number: IPCOM000002254D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 7 page(s) / 17K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Klensin: AUTHOR [+5]

Abstract

This memo defines an extension to the SMTP service whereby an SMTP client and server may interact to give the server an opportunity to decline to accept a message (perhaps temporarily) based on the client's estimate of the message size.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 18% of the total text.

Network Working Group J. Klensin, WG Chair

Request for Comments: 1427 United Nations University

N. Freed, Editor

Innosoft International, Inc.

K. Moore

University of Tennessee

February 1993

SMTP Service Extension

for Message Size Declaration

Status of this Memo

This RFC specifies an IAB standards track protocol for the Internet

community, and requests discussion and suggestions for improvements.

Please refer to the current edition of the "IAB Official Protocol

Standards" for the standardization state and status of this protocol.

Distribution of this memo is unlimited.

1. Abstract

This memo defines an extension to the SMTP service whereby an SMTP

client and server may interact to give the server an opportunity to

decline to accept a message (perhaps temporarily) based on the

client's estimate of the message size.

2. Introduction

The MIME extensions to the Internet message protocol provide for the

transmission of many kinds of data which were previously unsupported

in Internet mail. One expected result of the use of MIME is that

SMTP will be expected to carry a much wider range of message sizes

than was previously the case. This has an impact on the amount of

resources (e.g., disk space) required by a system acting as a server.

This memo uses the mechanism defined in [5] to define extensions to

the SMTP service whereby a client ("sender-SMTP") may declare the

size of a particular message to a server ("receiver-SMTP"), after

which the server may indicate to the client that it is or is not

willing to accept the message based on the declared message size and

whereby a server ("receiver-SMTP") may declare the maximum message

size it is willing to accept to a client ("sender-SMTP").

3. Framework for the Size Declaration Extension

The following service extension is therefore defined:

(1) the name of the SMTP service extension is "Message Size

Declaration";

(2) the EHLO keyword value associated with this extension is "SIZE";

(3) one optional parameter is allowed with this EHLO keyword value, a

decimal number indicating the fixed maximum message size in bytes

that the server will accept. The syntax of the parameter is as

follows, using the augmented BNF notation of [2]:

size-param ::= [1*DIGIT]

A parameter value of 0 (zero) indicates that no fixed maximum

message size is in force. If the parameter is omitted no

information is conveyed about the server's fixed maximum message

size;

(4) one optional parameter using the keyword "SIZE" is added to the MAIL

FROM command. The value associated with this parameter is a decimal

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