Auto Discover Service in Exchange 2007

Prior to Exchange 2007, users need to configure their outlook profiles manually by providing the correct exchange server name to access the Exchange server. By the autodiscover service in Exchange 2007, it seasier to configure Outlook 2007 or Outlook 2010 and some mobile phones(depends on the version and support). Autodiscover cannot be used with earlier versions of outlook like 2003.

The Autodiscover service uses a user's e-mail address and password to automatically configure a user's profile. Using the e-mail address, the Autodiscover service provides the following information to the client:

• The user’s display name
• Separate connection settings for internal and external connectivity
• The location of the user’s Mailbox server
• The URLs for various Outlook features that govern functionality such as free/busy information, Unified Messaging, and the offline address book
• Outlook Anywhere server settings

When a user's Exchange information is changed, Outlook automatically reconfigures the user's profile using the Autodiscover service. For example, if a user's mailbox is moved or the client can't connect to the user's mailbox or to available Exchange features, Outlook will contact the Autodiscover service and automatically update the user's profile to include the information that's required to connect to the mailbox and Exchange features.

When CAS role is installed on Exchange 2007 server,a new virtual directory named Autodiscover is created under the Default Web Site in Internet Information Services (IIS) and new service connection point (SCP) Active Directory object is created for each server where the Client Access server role is installed. The SCP object is used by domain-connected clients to locate the Autodiscover service. Autodiscover virtual directory in IIS handles Autodiscover service requests from Outlook 2007 clients in the following circumstances:

• When a new Outlook profile is configured or updated
• When a client periodically checks for changes to the Exchange Web Services URLs
• When underlying network connection changes occur in your Exchange messaging environment

Outlook connecting to exchange server using autodiscover in domain connected (internal access):

 Outlook first tries to connect to each Autodiscover URL that it had previously generated from either an in-site list (which the Autodiscover service is authoritative for that site)or an out-of-site list. If that doesn't work, Outlook will try to connect to the predefined URLs (for example, https://autodiscover.domain.com/autodiscover/autodiscover.xml) by using DNS. If that fails also, Outlook will try the HTTP redirect method and, failing that, Outlook will try to use the SRV record lookup method. If all lookup methods fail, Outlook will be unable to obtain Outlook Anywhere configuration and URL settings.

·  The Autodiscover service queries Active Directory to obtain the connection settings and URLs for the Exchange services that have been configured.

·  The Autodiscover service returns an HTTPS response with an XML file that includes the connection settings and URLs for the available Exchange services.

·  Outlook uses the appropriate configuration information and connection settings to connect to your Exchange messaging environment.

 Outlook connecting to exchange server using autodiscover in non domain environment(external or internet ):

When Outlook 2007 is started on a client that is not domain-connected, it first tries to locate the Autodiscover service by looking up the SCP object in Active Directory. Because the client is unable to contact Active Directory, it tries to locate the Autodiscover service by using Domain Name System (DNS). In this scenario, the client will determine right side of the user’s e-mail address, that is, contoso.com, and check DNS by using two predefined URLs. For example, if your SMTP domain is contoso.com, Outlook will try the following two URLs to try to connect to the Autodiscover service:

• https://domain.com/autodiscover/autodiscover.xml
• https://autodiscover.domain.com/autodiscover/autodiscover.xml 

Note:

1. For Outlook to be able to locate the Autodiscover service by using DNS, there must be a host record in DNS for the Autodiscover service that maps the entry point, or public IP address, to the Client Access server where the Autodiscover service is hosted.
2. Outlook and autodiscover service communication  happen on a secure channel i.e using SSL. So there should be a valid SSL cert installed on the server to work properly.