Network Working Group J. Shih
Internet Draft AT&T Corporation
Intended status: Proposed Standard June 13, 2011
Expires: December 2011
IMAP4 Server-Initiated LOGOUT Command
draft-shih-imap-server-logout-00.txt
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Abstract
Shih Expires December 13, 2011 [Page 1]
Internet-Draft IMAP4 Server-Initiated LOGOUT June 2011
The Internet Message Access Protocol [RFC3501] requires a client to
initiate a LOGOUT command to close the network connection. However,
it's often desirable to have the server initiate the termination of
the network connection. This allows the network to deactivate a
service provided to a client. This document specifies the syntax of a
server-initiated LOGOUT command, which will allow a server to tell
the client that the connection needs to be closed.
Table of Contents
1. Introduction ................................................. 2
2. Conventions used in this document ............................ 2
3. Specification ................................................ 3
4. Security Considerations ...................................... 3
5. IANA Considerations .......................................... 3
6. References ................................................... 3
7. Acknowledgments .............................................. 3
1. Introduction
In some situations, the network may need to deactivate a service
provided to a client. However, according to the current Internet
Message Access Protocol, Version 4rev1 (IMAP4rev1) [RFC3501], only a
client is allowed to originate the deactivation of an IMAP4rev1-based
service by sending a LOGOUT command to the server. This document
introduces a LOGOUT command sent out by a server. With this command,
a server is able to initiate the closing of a network connection when
necessary. This command informs the client of the server's intent to
close the connection so that the client will not regard the
disconnection as a malfunction when the server closes the connection.
2. Conventions used in this document
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lower case uses of these words are not to be
interpreted as carrying RFC-2119 significance.
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3. Specification
LOGOUT Command (initiated by the server)
Arguments: none
Responses: OPTIONAL untagged response: BYE
Result: OK - logout completed
BAD - command unknown or arguments invalid
A server sends a LOGOUT command to a client to inform the client that
the server needs to close the network connection. The client MAY send
a BYE untagged response before the (tagged) OK response. In order to
handle the case where a LOGOUT command can never trigger a final
response, a timer is implemented in the server. When a LOGOUT command
is sent to a client, the timer MUST be set for that particular
client. The timer MUST have a timing interval longer than 32 seconds.
The server SHALL close the connection when it receives the OK
response from the client or the timer expires.
Example: S: A001 LOGOUT
C: * BYE IMAP4rev1 Client logging out
C: A001 OK LOGOUT completed
(Server and client then close the connection)
4. Security Considerations
There are no known security issues with this extension.
5. IANA Considerations
6. References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3501] Crispin, M., "Internet Message Access Protocol - Version
4rev1", RFC 3501, March 2003.
7. Acknowledgments
This document was prepared using 2-Word-v2.0.template.dot.
Authors' Addresses
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Jerry Shih
AT&T
Email: jerry.shih@ATT.COM
Xin DING
ZTE Corporation
68 Zijinghua Road, Nanjing, China 210012
Email: ding.xin@zte.com.cn
Yan LU
ZTE Corporation
68 Zijinghua Road, Nanjing, China 210012
Email: luyan@zte.com.cn
Xiongwei Jia
China Unicom Research Institute
Email: jiaxw9@chinaunicom.cn
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