The Autodiscover service for Microsoft Exchange Server 2007 provides automatic profile configuration for Microsoft Office Outlook 2007 clients that are connected to your Exchange messaging environment.
When you install the Client Access server (CAS) role on a computer running Exchange 2007, a new virtual directory is created under the Default Web Site in Internet Information Services (IIS). In the Active Directory a Service Connection Point (SCP) object is created that allows all domain-connected clients running Outlook 2007 to query the Active Directory and configure the Outlook profile automatically.
Many organizations have complex topologies with multiple forests where the Exchange is running in a resource forest and an accounts forest which contains the user accounts for the organization. In the multiple trusted forest scenario, the user accounts and Microsoft Exchange are deployed in multiple forests. Exchange 2007 features such as the Availability service and Unified Messaging rely on the Autodiscover service to access user accounts across forests. In this scenario, the Autodiscover service must be available to users across multiple trusted forests.
The intention of this post is not to explain how Autodiscover works, how to implement it for multiple forests, or troubleshoot every scenario. It is a brief, practical list of tips for use during the deployment and covers some common examples and methods to resolve issues.
For more details how Exchange 2007 Autodiscover works and deployment considerations, see the white paper:
Microsoft, Exchange Server 2007, Autodiscover, Configuration, Troubleshooting, Tips, Tricks, Tips and Tricks