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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-42833109-F8C2-57FC-9995-0461698A19FF" xml:lang="en"><title>IMAP4

Concepts</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This section describes the Internet Message Access Protocol (IMAP4) and

its implementation on the Symbian platform. </p>

<section id="GUID-DBF1C87D-7360-54B7-8658-B6659BF77F06-GENID-1-10-1-17-1-1-6-1-5-1-4-1-2-2"><title>IMAP4 protocol</title> <p>IMAP4

is one of the most common Internet standard protocols for retrieving emails.

It is an application layer Internet protocol operating on port 143 that allows

a local client to access email on a remote server. </p> <p>The current version,

IMAP version 4 revision 1 (IMAP4rev1), is defined by RFC 3501. Eariler, IMAP4

was called Internet Mail Access Protocol, Interactive Mail Access Protocol

(RFC 1064), and Interim Mail Access Protocol. </p> <p>The default port for

IMAP4 to download messages is 143, but if a client establishes a secure connection

(over SSL or TLS) for IMAP4 to download message, the port is 993. </p> <p>Most

email clients support either POP3 or IMAP to retrieve messages; however, few

Internet Service Providers (ISPs) support IMAP. IMAP4 supports access to the

mail store in both modes of operation—connected (online) and disconnected

(offline). </p> <p>Emails are generally sent to an email server that stores

received messages in the recipient's email mailbox. The user later retrieves

these messages with either a web browser or an email client that uses one

of a number of email retrieval protocols. </p> <p>Email clients using IMAP4

generally stores messages on the server until the user explicitly deletes

them. This allows multiple clients to access the same mailbox. However, the

client may store local copies of the messages, but these are considered to

be a temporary cache; the server's store is authoritative. </p> </section>

<section id="GUID-6162DB96-ED81-4AA4-B737-8298DC0A94D1"><title>Symbian platform implementation of IMAP4</title> <p>The Messaging

Application module has implemented all the functionality of standard IMAP4

and conforms to RFC3501. </p> </section>

<section id="GUID-572840C2-0ECC-4925-A42D-093E0043E07F"><title>IMAP4 example</title> <p>For more details on implementing

the IMAP4 MTM functions, see <xref href="GUID-D73AD200-BE4D-50BF-BCF9-14627DE530B7.dita">example

code</xref>. </p> </section>

</conbody><related-links>

<link href="GUID-1F755804-70D6-5635-B2F7-06F03C8D4B74.dita"><linktext>IMAP4 MTM</linktext>

</link>

</related-links></concept>