MSA requires authentication before accepting a message, and the MTA
rejects all RCPT commands for non-local users. This can be an
important element in a site’s total email security policy.
If a site fails to require any form of authorization for message
submissions (see section 3.3 for discussion), it is allowing open use
of its resources and name; unsolicited bulk email can be injected
using its facilities.
Section 3 includes further discussion of issues with some
authentication methods.
Section 5.2 includes a cautionary note that unlimited logging can
enable certain forms of denial of service attacks.
10. IANA Considerations
The registration for port 587 has been updated to refer to this memo
rather than RFC 2476.
11. Acknowledgements
Nathaniel Borenstein and Barry Leiba were instrumental in the
development of this update to RFC 2476.
The original memo (RFC 2476) was developed in part based on comments
and discussions which took place on and off the IETF-Submit mailing
list. The help of those who took the time to review that document
and make suggestions is appreciated, especially that of Dave Crocker,
Ned Freed, Keith Moore, John Myers, and Chris Newman.
Special thanks to Harald Alvestrand, who got this effort started.
12. Normative References
[ESMTP] Klensin, J., Freed, N., Rose, M., Stefferud, E.,
and D. Crocker, "SMTP Service Extensions", STD 10,
RFC 1869, November 1995.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[SMTP-MTA] Postel, J., "Simple Mail Transfer Protocol", STD
10, RFC 821, August 1982.
Partridge, C., "Mail routing and the domain
system", STD 10, RFC 974, January 1986.
Braden, R., "Requirements for Internet Hosts -
Application and Support", STD 3, RFC 1123, October
1989.
Klensin, J., "Simple Mail Transfer Protocol", RFC
2821, April 2001.
13. Informative References
[521REPLY] Durand, A. and F. Dupont, "SMTP 521 Reply Code",
RFC 1846, September 1995.
[8BITMIME] Klensin, J., Freed, N., Rose, M., Stefferud, E.,
and D. Crocker, "SMTP Service Extension for 8bit-
MIMEtransport", RFC 1652, July 1994.
[CHECKPOINT] Crocker, D., Freed, N., and A. Cargille, "SMTP
Service Extension for Checkpoint/Restart", RFC
1845, September 1995.
[CHUNKING] Vaudreuil, G., "SMTP Service Extensions for
Transmission of Large and Binary MIME Messages",
RFC 3030, December 2000.
[CODES-EXTENSION] Freed, N., "SMTP Service Extension for Returning
Enhanced Error Codes", RFC 2034, October 1996.
[DSN] Moore, K., "Simple Mail Transfer Protocol (SMTP)
Service Extension for Delivery Status Notifications
(DSNs)", RFC 3461, January 2003.
[ETRN] De Winter, J., "SMTP Service Extension for Remote
Message Queue Starting", RFC 1985, August 1996.
[IMAP4] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL -
VERSION 4rev1", RFC 3501, March 2003.
[IPSEC] Kent, S. and R. Atkinson, "Security Architecture
for the Internet Protocol", RFC 2401, November
1998.
[MESSAGE-FORMAT] Crocker, D., "Standard for the format of ARPA
Internet text messages", STD 11, RFC 822, August
1982.
Braden, R., "Requirements for Internet Hosts -
Application and Support", STD 3, RFC 1123, October
1989.
Resnick, P., "Internet Message Format", RFC 2822,
April 2001.
[Msg-Track] Allman, E. and T. Hansen, "SMTP Service Extension
for Message Tracking", RFC 3885, September 2004.
[PIPELINING] Freed, N., "SMTP Service Extension for Command
Pipelining", STD 60, RFC 2920, September 2000.
[POP3] Myers, J. and M. Rose, "Post Office Protocol -
Version 3", STD 53, RFC 1939, May 1996.
[SIZE] Klensin, J., Freed, N., and K. Moore, "SMTP Service
Extension for Message Size Declaration", STD 10,
RFC 1870, November 1995.
[SMTP-AUTH] Myers, J., "SMTP Service Extension for
Authentication", RFC 2554, March 1999.
[SMTP-CODES] Vaudreuil, G., "Enhanced Mail System Status Codes",
RFC 3463, January 2003.
[Start-TLS] Hoffman, P., "SMTP Service Extension for Secure
SMTP over Transport Layer Security", RFC 3207,
February 2002.
Authors’ Addresses
Randall Gellens
QUALCOMM Incorporated
5775 Morehouse Drive
San Diego, CA 92121-2779
USA
EMail: rg+ietf@qualcomm.com
John C. Klensin
1770 Massachusetts Ave, #322
Cambridge, MA 02140
USA
EMail: john+ietf@jck.com
Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgement
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).