The Autodiscover Process
There are two steps to the Autodiscover process. The first step consists of finding the Autodiscover service and the second step includes querying the Autodiscover service for the desired services. Since Microsoft Exchange is the Autodiscover service as well as the ActiveSync server, the Autodiscover process consists of the device first connecting to the Autodiscover service to submit the query for the ActiveSync server address and then using the ActiveSync server address for all future communication with the server.
Multiple connections are used (as opposed to just generating the ActiveSync server address based on the email address domain) because it is often required that a very specific server address value is used when using SSL to protect communication between the device and the ActiveSync server. This server address may not always match the email address domain, which would make it impossible for the device to locate the server automatically.
Autodiscover Location Discovery