There are alot of resources available at this point of time with regards to the 'Autodiscovery', which is now an old friend of ours. However, considering that a lot about it is scattered throughout, here's a brief personality of 'autodiscovery' for those who look to be friend of it:
At installation of CAS Role, SCP AD Object is automatically created. Number of SCPs created will be equal to the number of CAS roles you have.
Also with the installation of CAS role, a virtual directory "AUTODISCOVER" is created in IIS which handles the autodiscover service requests from OL2k7/OL2k10/Supported mobile devices
Circumstances in which these autodiscover service requests are handled are:
New profile creation/modification - When a new user account is configured or updated.
Changes in Exch Web Service URLs - When a user periodically checks for changes to the Exchange Web Services URLs.
Changes in n/w connections - When underlying network connection changes occur in your Exchange messaging environment.
Important attributes on a SCP which are used to connect to and authenticate the service instance are:
When a Client is launched, it searches for the attribute "keyword" in AD (GC) to locate SCP. Once SCP is located, the client can read other attributes of that SCP to retrieve service data
In Case Of Internal OL 2k7/2k10 Client:
When OL2k7/2k10 is launched, it will contact AD for AutoDiscover Information.
AD on this request will return a list of SCPs
OL Client will select the first SCP in the provided list of SCPs by AD
OL Client then try to connect to the CAS Role using HTTPS for which the information is present in the selected SCP.
Autodiscover service on CAS then returns addresses of available services to client (OOF,OAB,Etc.)
The SCP information includes authoritative list of Autodiscover service URLs for the forest where Exchange 2007 is installed:
The user’s display name.
Separate connection settings for internal and external connectivity.
The location of the user’s Exchange 2007 server that has the Mailbox server role installed.
The URLs for Exchange features such as free/busy information, UM, and the OAB.
Outlook Anywhere server settings. Outlook Anywhere was formerly known as RPC over HTTP.
In Case Of External OL 2k7/2k10 Client:
OL tries to contact AD which fails
Since OL Client cannot contact AD, it will take domain information from the email address entered while configuring OL Client
For email, email@example.com it will check for the following URLs:
[contained in serviceBindingInformation]
Autodiscover service from CAS will return the URLs for MS Exchange Features
OL then connects to the Exchange Features
Now further going into deep, when OL Client makes requests to AutoDiscover Service, the AutoDiscover service contacts the "Outlook Provider" located under the SCP in AD-DS
Outlook Providers are used to provide the configuration settings as requested by OL clients depending on the type of client.
There are three Outlook Provider Settings depending on type of client:
EXCH Settings - which includes port settings and internal URL for enabled exchange services
EXPR Settings - which includes external URL for enabled exchange services used by clients over internet
WEB Settings - which includes URL for the OWA for a user. This setting in not in use
Outlook Provider settings can be viewed or changed using Get-OutlookProvider and Set-OutlookProvider
How to Diagnose Availability Service Issues:
Test-OutlookWebServices -Identity: User1@Contoso.com
For CAS Role
Test-OutlookWebServices -ClientAccessServer ClientAccessServer01
For across different site
Test-OutlookWebServices -Identity User1@Site1.Contoso.com -TargetAddress User2@Site2.Fabrikam.com
Using Test E-Mail AutoConfiguration from client machine
To manually force the Autodiscover service to update the user's profile settings:
Open Outlook 2007.
In Outlook 2007, click Tools, and then click Account Settings.
On the E-mail Accounts page, on the E-mail tab, click Repair.
Follow the steps in the Repair E-mail Account wizard.
Few articles for thought and some of the technet articles have been used in this Article:
Exchange 2k7 Autodiscover Service:
More about Outlook Providers:
Modifying Outlook Providers: