Internet Draft: Notify Mail R. Gellens
Document: draft-gellens-notify-mail-00.txt QUALCOMM
Expires: January 2005 July 2004
Simple New Mail Notification
Status of this Memo
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Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This memo documents a long-standing technique supported by a large
number of mail servers which allows users to be notified of new
mail. In addition to server support, there are a number of clients
which support this, ranging from full email clients to specialized
clients whose only purpose is to receive new mail notifications and
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alert a mail client.
In brief, the technique is for the server to send the string
"nm_notifyuser" to the finger port on the IP address (either
configured or last used) for the user who has received new mail.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in this Document . . . . . . . . . . . . . . 3
3. Simple Mail Notification . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
8. Informative References . . . . . . . . . . . . . . . . . . . . 4
9. Author's Addresses . . . . . . . . . . . . . . . . . . . . . 5
Intellectual Property Statement . . . . . . . . . . . . . . . . 5
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 5
Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
There is a long-standing technique supported by a large number of
mail servers which allows users to be notified of new mail. In
addition to server support, there are a number of clients which
support this, ranging from full email clients to specialized clients
whose only purpose is to receive new mail notifications and alert a
mail client. This technique is sometimes known as "notify mail"
(after a shareware client of the same name), sometimes called
"biff", and sometimes the "finger hack".
2. Conventions Used in this Document
In examples, "C:" is used to indicate lines sent by the client, and
"S:" indicates those sent by the server. Line breaks within a
command example are for editorial purposes only.
Examples use the 'example.net' domain.
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as defined in [KEYWORDS].
3. Simple Mail Notification
The technique is for the server to send the string "nm_notifyuser"
to the finger port on the IP address for the user who has received
new mail.
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The IP address to use may be configured, or the server may use the
IP address that was last used to check mail by the user. Typically
this is a per-account configuration option.
To be useful, on the client system a process must be listening to
the finger port. When it received the "nm_notifyuser" string, it
takes a configured action, typically instructing a mail client to
fetch mail.
Normally, the a TCP connection to the target computer is opened, the
"nm_notifyuser" string is sent, and the connection is closed without
waiting for any response.
In some cases UDP is used instead of TCP.
4. Security Considerations
There is of course no assurance that in general the "nm_notifyuser"
message is being sent to the correct IP address. Nor does the
listening agent on the client system have any assurance that a
"nm_notifyuser" string was sent by a mail server which has received
new mail for the user. It would be trivial for an attacker to send
large numbers of "nm_notifyuser" messages to any targeted system.
Client systems listening for this message SHOULD implement
protections against being flooded with notifications. Many server
systems already implement protections against users logging in and
checking mail too frequently.
5. IANA Considerations
None at this time.
6. Acknowledgments
The NotifyMail shareware utility was written by Scott Gruby.
7. Normative References
[KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", March 1997, BCP 14, RFC 2119,
<ftp://ftp.isi.edu/in-notes/rfc2119.txt>
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8. Informative References
None.
9. Author's Addresses
Randall Gellens
QUALCOMM Incorporated
6455 Lusk Blvd.
San Diego, CA 92121-2779
USA
randy@qualcomm.Com
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Full Copyright Statement
Copyright (C) The Internet Society (2004).
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.
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Disclaimer
This document and the information contained herein are provided on
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