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- Network Working Group Greg Vaudreuil
- Internet Draft Tigon Corporation
- Expires: 4/18/94 October 18, 1993
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- SMTP Service Extensions
- for Command Streaming
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- <draft-vaudreuil-smtp-stream-00.txt>
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- 1.Status of this Memo
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- This document is an Internet Draft. Internet Drafts are working
- documents of the Internet Engineering Task Force (IETF), its Areas,
- and its Working Groups. Note that other groups may also distribute
- working documents as Internet Drafts.
-
- Internet Drafts are valid for a maximum of six months and may be
- updated, replaced, or obsoleted by other documents at any time. It is
- inappropriate to use Internet Drafts as reference material or to cite
- them other than as a "work in progress".
-
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- 2.Abstract
-
- This memo defines an extension to the SMTP service whereby an SMTP
- client and server may negotiate the use of a command streaming
- implementation model for SMTP. This model enables the batching of the
- all commands between the EHLO and DATA command. This extension
- significantly reduces the number of packets and round trips to send a
- message. Batching the MAIL FROM and RCPT TO commands for multiple
- receipients significantly decreases the protocol processing overhead
- when sending messsages to multiple receipients.
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- 3.Introduction
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- One source of inefficiency in the use of SMTP, especially when used in
- in a central mail hub, is the implicit requirement to send the full
- SMTP command stream, including each RCPT TO command sychronously, that
- is, to wait for a response to the previous command before sending the
- next. This stop and wait interaction often adds minutes to the length
- of a SMTP session, partly when validation of addresses may require
- non-local table lookup.
-
- This memo uses the mechanism defined in [4] to define extensions to
- the SMTP service whereby a client ("sender-SMTP") may declare support
- for a atreaming command mode.
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- 4.Framework for the Binary Extensions
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- The following service extension is hereby defined:
-
- 1) The name of the service extension is "Stream"
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- 2) The EHLO keyword value associated with this extension is
- "STREAM"
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- 3) No parameter is used with the STREAM keyword
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- 5.The Stream service extension
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- When a client SMTP wishes to submit (using the MAIL command) a content
- body consisting of a MIME message containing arbitrary octet-aligned
- material, it first issues the EHLO command to the server SMTP. If the
- server SMTP responds with code 250 to the EHLO command, and the
- response includes the EHLO keyword value STREAM, then the server SMTP
- is indicating that it supports the command streaming implementation
- model and will the batching of all commands between the EHLO and the
- accept MIME messages containing arbitrary octet-aligned material.
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- After receiving the 250 response to the EHLO command with the STREAM
- keyword, the MAIL FROM and RCPT TO commands can optionally be
- sent as a block. If the MAIL FROM address is invalid or otherwise
- unavailable, the following RCPT TO commands should be answered with
- the 503 command out of sequence error.
-
- Note: While SMTP does not explicitly require the stop and wait
- behavior, and while the protocol as defined will work in a
- streaming model, the examples have led implementors to build SMTP
- servers in such a manner as to require this behavior. This
- service extension recognizes the desire to use a streaming
- implementation model and explicitly encourages its use.
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- Vaudreuil [Page 2]
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- 6.Usage Examples
-
- The following dialogue illustrates the use of the stream service
- extension to send a 7BIT object to three recipients without the stop
- and wait for an explicit 250 for each recipient:
-
- S: <wait for connection on TCP port 25>
- C: <open connection to server>
- S: 220 cnri.reston.va.us SMTP service ready
- C: EHLO ymir.claremont.edu
- S: 250-cnri.reston.va.us says hello
- S: 250 STREAM
- C: MAIL FROM:<ned@ymir.claremont.edu>
- C: RCPT TO:<vcerf@cnri.reston.va.us>
- C: RCPT TO:<gvaudre@cnri.reston.va.us>
- C: RCPT TO:<jstewart@cnri.reston.va.us>
- S: 250 <ned@ymir.claremont.edu>... Sender ok
- S: 250 <vcerf@cnri.reston.va.us>... Recipient ok
- S: 250 <gvaudre@cnri.reston.va.us>... Recipient ok
- S: 250 <jstewart@cnri.reston.va.us>... Recipient ok
- C: DATA
- S: 354 Send message, terminated by a dot.
- ...
-
- .
- S: 250 OK
- C: QUIT
- S: 250 Goodbye
-
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- 7.Security Considerations
-
- This RFC does not discuss security issues and is not believed to raise
- any security issues not already endemic in electronic mail and present
- in fully conforming implementations of [1].
-
- 8.Acknowledgements
-
- This document is the result of numerous discussions in the IETF SMTP
- Extensions Working Group. Text for this document was liberally copied
- from RFC 1426 by John Klensin, Marshall Rose, Need Freed, Dave
- Crocker, and Einar Stefferud.
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- Vaudreuil [Page 3]
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- Internet Draft Expires 4/18/94
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- 9.References
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- [1] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
- USC/Information Sciences Institute, August 1982.
-
- [2] Crocker, D., "Standard for the Format of ARPA Internet Text
- Messages", STD 11, RFC 822, UDEL, August 1982.
-
- [3] Borenstein, N., and N. Freed, "Multipurpose Internet Mail
- Extensions", RFC 1341, Bellcore, Innosoft, June 1992.
-
- [4] Klensin, J., WG Chair, Freed, N., Editor, Rose, M.,
- Stefferud, E., and D. Crocker, "SMTP Service Extensions" RFC
- 1425,
-
- [5] Klensin, J., WG Chair, Freed, N., Editor, Rose, M.,
- Stefferud, E., and D. Crocker, "SMTP Service Extension for 8bit-
- MIMEtransport" RFC 1426, United Nations University, Innosoft
- International, Inc., Dover Beach Consulting, Inc., Network
- Management Associates, Inc., The Branch Office, February 1993.
-
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- 10. Author's Address
-
- Gregory M. Vaudreuil
- The Tigon Corporation
- 17080 Dallas Parkway
- Dallas, TX 75248-1905
- 214-733-2722
- Gvaudre@cnri.reston.va.us
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- Vaudreuil [Page 4]
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