Microsoft Exchange Server 2007 has a new trick up its sleeve in combination with Microsoft Office Outlook 2007 and Windows Mobile 6: Exchange AutoDiscover Service. You can use this feature with your Domain Naming System (DNS) implementation, but this feature is even more functional when used in conjunction with Active Directory.
(Just like everything you use in your daily life…)

Before AutoDiscovery

In Microsoft Exchange 2000 Server and Microsoft Exchange Server 2003 environments you had to use elaborate %username% tricks, work with the Microsoft Office Custom Installation Wizard, Newprof, Profgen or any of the hundreds tools and scripts available for the purpose of automatically configuring Microsoft Outlook to use your Microsoft Exchange messaging infrastructure.

Better together

Microsoft introduced the marketing phrase "better together" for Microsoft Office Outlook 2003 and Microsoft Exchange Server 2003 and they told us Knowledge and Information Workers could benefit from increased performance and availability features, like:

• Improved MAPI compression
• Unicode Offline Folders (OST files)
• RPC over HTTP(s)

With Microsoft Office Outlook 2007 and Microsoft Exchange Server 2007 the phrase "Better together" gets reused. The dust is blown off, it got a good polish and it looks like brand new! This time Microsoft uses it to sell the new featureset, including:

• Improved Out of Office (OoO) Assistant
• New Scheduling Assistant
• AutoDiscover
• Instant Search
• Sharing policies
• Managed E-mail folders
• AutoDiscover feature

How it works

To make this clear right from the start: AutoDiscover is a web service. It is served by Microsoft Exchange Server 2007 boxes with the Client Access Server Role on them. (also known as a Client Access Server) A DNS record (optional) and a Service Connection Point within Active Directory point to the AutoDiscover server.

From the client part AutoDiscover-enabled clients use the information within your DNS zone to find the server hosting the Web Service. With AutoDiscover-enabled clients I mean:

• Microsoft Outlook 2007 installations on PC's within your organization
• Microsoft Outlook 2007 installations you want to use with Outlook Anywhere (formerly known as RPC over HTTP clients)
• Microsoft Windows Mobile 6 devices

Server-side

Let's look into each of the server-side components that make up the AutoDiscover Web Service a bit closer:

Domain Naming System (DNS) or Active Directory Lookup

When you install Microsoft Exchange server 2007 the installation program creates an Active Directory object in your Active Directory known as a Service Connection Point.

You can also make a DNS A record in your Forward Lookup zone within your DNS Management MMC Snap-in (dnsmgmt.msc) pointing to the IP address of your Microsoft Exchange Server. The name of this record would be autodiscover.

Using Active Directory Integrated DNS in your enterprise organization makes this task easy: The changes you make in DNS will be replicated through your organization without a hitch and in a multi-master manner.

When you plan multiple Microsoft Exchange Servers with the Client Access Role I suggest you make multiple DNS records with the name autodiscover to point to these servers. That way you won't end up with a single point of failure (SPoF) for this service. the Client Access Servers will point the connecting client to the appropriate Exchange Server.

Using the automatically created AutoDiscover Service Connection Point is the preferred way to go, because you can use it in conjunction with Active Directory sites. The Exchange Team said Microsoft Exchange Server 2007 is Active Directory site-aware and it shows again.

If you want to enable Microsoft Windows Mobile 5.0 MSFP or Windows Mobile 6.0 devices and Outlook Anywhere clients you should also make a DNS A record in your public Forward Lookup Zone, resulting in a autodiscover.youremaildomain.com DNS record pointing towards a public IP address where you'd make the AutoDiscover IIS Virtual Folder available through HTTP over SSL (HTTPS) and make sure you publish it with a valid SSL Certificate to avoid unnecessary errors.

The Autodiscover Virtual Server

Within the Internet Information Services (IIS) Manager on your Microsoft Exchange Server with the Client Access role (known as a Client Access Server) you'll find an IIS Virtual Server called 'autodiscover'. It contains multiple files and subfolders:

• Folder: Help
• Folder: Bin
• Autodicover.xml
• default.aspx
• global.asax
• web.config

Managing AutoDiscovery Services

The Microsoft Exchange Management Shell provides some splendid CMDlets to manage the Autodiscover Service on Microsoft Exchange Server 2007 Client Access Servers:

• New-AutoDiscoverVirtualDirectory and Remove-AutoDiscoverVirtualDirectory to create new AutoDiscover Virtual Directories or to remove the original or manually created AutoDiscover Virtual Directories on your Client Access Servers
• Test-OutlookWebServices with the -ClientAccessServer switch to test your AutoDiscover Services.
• Set-AutoDiscoverVirtualDirectory lets you configure the behavior of your AutoDiscover Virtual Directory (so you don't have to edit your Autodiscover.xml manually), while Get-AutoDiscoverVirtualDirectory retrieves settings from AutoDiscover Virtual Directories.
• You can make or delete the AutoDiscovery Services' Service Connection Point in Active Directory with the Export-AutoDiscoverConfig CMDlet.

Besides the cmdlets to configure individual AutoDiscover Virtual Directories there are four cmdlets that grant you the ability to manage the AutoDiscoverConfig object under the Global Settings object in the Active Directory directory service. These are New-OutlookProvider, Remove-OutlookProvider, Get-OutlookProvider and Set-OutlookProvider. These settings can also be managed using AdsiEdit.msc from the Support Tools if that is your preferred way of editing the Exchange Organization within Active Directory, but I must admit that the more granular way of granting permissions in Exchange Server 2007 appeals to me more.

Last but not least the Set-ClientAccessServer CMDlet offers you the chance to enter the AutoDiscoverSiteScope option to define for which Active Directory sites the Autodiscover service is authoritative.

Conclusion

The Outlook 2007 AutoDiscover web service is awesome!

Further reading

Overview of the Autodiscover Service
Autodiscover and Exchange 2007
Deployment Considerations for the Autodiscover Service
Uncovering the New Outlook 2007 AutoConnect feature
Better Together: Outlook 2003 and Exchange Server 2003
Better Together: Outlook 2007 and Exchange Server 2007
What does Exchange 2007 Availability Service do?
Publishing with Service Connection Points
MSDN – Exchange Server 2007 Autodiscover Reference
Microsoft Technet – Managing the Autodiscover Service
Outlook Automatic Account Configuration whitepaper
How do I configure Outlook 2007 using AutoDiscovery?

Disclaimer Beta Software

The information on this webpage applies to software from Microsoft that was in testing phase but utilizable by experienced users by the time the webpage was written. This software has not been released for sale, distribution or usage for the general public. The information on this webpage and the beta software are provided "as is" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose.