RFC 1845 (rfc1845) - Page 1 of 7
SMTP Service Extension for Checkpoint/Restart
Alternative Format: Original Text Document
Network Working Group D. Crocker
Request For Comments: 1845 Brandenburg Consulting
Category: Experimental N. Freed
Innosoft International, Inc.
A. Cargille, WG Chair
September 1995
SMTP Service Extension
for Checkpoint/Restart
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. This memo does not specify an Internet standard of any
kind. Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Abstract
This memo defines an extension to the SMTP service whereby an
interrupted SMTP transaction can be restarted at a later time without
having to repeat all of the commands and message content sent prior
to the interruption.
1. Introduction
Although SMTP is widely and robustly deployed, various extensions
have been requested by parts of the Internet community. In
particular, when dealing with very large messages over less reliable
connections it is possible for substantial resources to be consumed
by repeated unsuccessful attempts to transmit the message in its
entirety. The original SMTP specification [1] does not provide any
means to pick up a partially completed transaction after the
underlying TCP connection has been broken and reestablished.
This memo provides a facility by which a client can uniquely identify
a particular SMTP transaction. The server then stores this
identifying information along with all the information it receives as
the transaction proceeds. If the transaction is interrupted during
the data transfer phase the SMTP client may establish a new SMTP
session at a later time and ask the server to continue the
transaction from the point where the server lost its connection with
the client. The server then reestablishes the transaction context and
tells the client where to resume operations. If this is acceptable
the client resumes operations at this point.
Crocker, Freed & Cargille Experimental