Understanding Exchange ActiveSync

Applies to: Exchange Server 2010

Topic Last Modified: 2010-01-12

By default, when you install the Client Access server role on a computer that's running Microsoft Exchange Server 2010, you enable Microsoft Exchange ActiveSync. Exchange ActiveSync lets you synchronize a mobile phone with your Exchange 2010 mailbox.

Exchange ActiveSync is a Microsoft Exchange synchronization protocol that's optimized to work together with high-latency and low-bandwidth networks. The protocol, based on HTTP and XML, lets mobile phones access an organization's information on a server that's running Microsoft Exchange. Exchange ActiveSync enables mobile phone users to access their e-mail, calendar, contacts, and tasks and to continue to be able to access this information while they're working offline.

Exchange ActiveSync can synchronize e-mail messages, calendar items, contacts, tasks, and notes.

Exchange ActiveSync provides the following:

  • Support for HTML messages
  • Support for follow-up flags
  • Support for fast message retrieval
  • Meeting attendee information
  • Enhanced Exchange Search
  • Windows SharePoint Services and Windows file share (UNC) document access
  • PIN reset
  • Enhanced device security through password policies
  • Autodiscover for over-the-air provisioning
  • Support for setting auto-replies when users are away, on vacation, or out of the office
  • Support for tasks synchronization
  • Direct Push

By default, Exchange ActiveSync is enabled. All users who have an Exchange mailbox can synchronize their mobile phone with the Microsoft Exchange server.

You can perform the following Exchange ActiveSync tasks:

  • Enable and disable Exchange ActiveSync for users
  • Set policies such as minimum password length, device locking, and maximum failed password attempts
  • Initiate a remote wipe to clear all data from a lost or stolen mobile phone
  • Run a variety of reports for viewing or exporting into a reporting solution

You can configure Exchange ActiveSync to use Secure Sockets Layer (SSL) encryption for communications between the Exchange server and the mobile phone client. Certificate-based authentication works with a self-signed certificate, a certificate from an existing public key infrastructure, or a third-party commercial certificate. You can use certificate-based authentication together with other security features, such as local device wipe and a device password, to turn the mobile phone into a smartcard. The private key and certificate for client authentication are stored in memory on the mobile phone. If an unauthorized user tries to bypass the mobile phone password, all user data is purged. This includes the certificate and private key. For more security, you can deploy RSA SecurID two-factor authentication on the Exchange server.

In addition to the ability to configure security options for communications between the Exchange server and your mobile phones, Exchange ActiveSync offers the following features to enhance the security of mobile phones:

  • Remote wipe   If a mobile phone is lost, stolen, or otherwise compromised, you can issue a remote wipe command from the Exchange Server computer or from any Web browser by using Outlook Web App. This command erases all data from the mobile phone.
  • Device password policies   Exchange ActiveSync lets you configure several options for device passwords. These options include the following:
    • Minimum password length (characters)   This option specifies the length of the password for the mobile phone. The default length is 4 characters, but as many as 18 can be included.
    • Require alphanumeric password   This option determines password strength. You can enforce the usage of a character or symbol in the password in addition to numbers.
    • Inactivity time (seconds)   This option determines how long the mobile phone must be inactive before the user is prompted for a password to unlock the mobile phone.
    • Wipe device after failed (attempts)   This option lets you specify whether you want the phone's memory to be wiped after multiple failed password attempts.