16.8. Microsoft Messaging API (MAPI)
The Microsoft Messaging API
(MAPI) is, as the name implies, an application programming interface
(API) and not a network protocol at all. It is included here because
for various reasons, including the uncanny resemblance of its name to
"IMAP", it is often mistaken for a mail protocol. MAPI is
used on Microsoft operating systems for applications to communicate
with messaging systems. It is internal to a single machine; an
application uses MAPI to communicate with MAPI drivers, which then
communicate with mail and directory servers. A MAPI driver will use
whatever protocol it needs to in order to communicate with mail and
directory servers. This means that applications that are programmed
with MAPI can be used with a variety of email servers without
changes, by changing the MAPI drivers.
Knowing that an application uses MAPI does not allow you to predict
what protocol will be used to communicate between a client and a
server. Instead, you need to know what protocols the MAPI driver is
using; usually the easiest way to determine this is to determine what
kind of server is being used. Probably the biggest user of MAPI is
the Microsoft Exchange client, which is provided with MAPI drivers
that use Microsoft RPC to speak to Microsoft Exchange
servers.
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16.7. Internet Message Access Protocol | | 16.9. Network News Transfer Protocol |