Monday, September 28, 2015

Autodiscover and Outlook

We see lots of confusion in our customer base about the function that Autodiscover serves in both traditional on-premises environments and cloud-based environments alike. At a high level, Autodiscover basically allows you to skip all the back-end configuration work that legacy mail clients need and have the Outlook email client do it all for you.

In environments with Active Directory, getting Autodiscover to work properly can be more trouble than it should be, but with access to group policies and a bit of information, you'll be able to get it working.

What is Autodiscover?

Autodiscover is a service that runs in the background of your Exchange or Office 365 install and can automatically configure profile settings for users running Outlook 2007 or newer, Mac Mail, or mobile phones. It provides access to Exchange features for Outlook 2007 and up clients that are connected to your Exchange messaging environment, and it uses a user's email address and password to provide profile settings to supported clients and devices. If the Outlook client is joined to a domain, the user's domain account is used.

In earlier versions of Microsoft Exchange (2003 SP2 or earlier) and Outlook (2003 or earlier), you had to configure all user profiles manually to access Exchange; Autodiscover negates the need for this manual setup. Extra work was required to manage these profiles if changes occurred in the environment and if this maintenance stopped or fell behind schedule, Outlook clients could stop functioning entirely.

Autodiscover is a function of Exchange (and, in a roundabout way, therefore also a function of Office 365). Outlook clients are coded in such a way that they can take advantage of Autodiscover, but for this to work correctly, Outlook needs to be told where to "find" the Autodiscover information. The order of logic that Outlook uses when trying to retrieve information is:
  • Service Connection Point (SCP) lookup  Outlook will get Autodiscover information from Active Directory. If this fails, Outlook begins its 'non-domain' connections;
  • HTTPS root domain query;
  • HTTPS Autodiscover domain query;
  • HTTP redirect method;
  • SRV record query;
  • Local XML file;
  • Cached URL in the Outlook profile (exclusive to Outlook 2013 and newer).

How does Autodiscover work?

When you install a Client Access Server in Exchange 2013, a default virtual directory named Autodiscover is created under the default website in Internet Information Services (IIS). This virtual directory handles Autodiscover service requests from supported clients under the following circumstances:
  • When a user account is created or updated;
  • When an Outlook client periodically checks for changes to the Exchange Web Services URLs;
  • When underlying network connection changes occur in your Exchange environment.
Additionally, a new Active Directory object named the SCP is created on the server where you install the Client Access Server.

The SCP object contains the authoritative list of Autodiscover service URLs for the entirety of your Active Directory forest. (You can use the Set-ClientAccessServer cmdlet to update the SCP object.)

How to manually override Autodiscover service for your PC

Occasionally, Outlook clients can "find" incorrect Autodiscover settings – we find this is most common when businesses decide to switch to Office 365 from an on-premises Exchange environment. Here's how you can force Outlook to stop looking for Autodiscover
  1. Click Start, and then click run
  2. In the Run dialog box, type regedit, and then click OK
  3. In the Registry Editor, go to the following registry key:
    • HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Autodiscover
    • Create a new DWORD (32-bit) string named "ExcludeScpLookup" and set its value to 1.
You can alternatively use the command prompt to exclude SCP lookups by using following commands:
reg add HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Autodiscover /v

ExcludeScpLookup /t reg_dword /d 1 /f
Hopefully this has helped you get a better understanding of how Autodiscover works for Outlook as well as how to override default priorities.

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