To access public folders by using the original release (RTM) version of Exchange 2007 version of Outlook Web Access, the following requirements must be met:

• The home public folder server for the mailbox database must be a server that is running Microsoft Exchange Server 2003 or Microsoft Exchange 2000 Server. You can set the home public folder server by using the Set-MailboxDatabase cmdlet and the publicfolderdatabase parameter.
  
• You must use a dedicated server for the Client Access server role. If the server that hosts the Client Access server role also hosts the Mailbox server role, public folder access may be unreliable through that server when users are accessing Outlook Web Access by using the Internet.
  

Public folders do not appear in the default Outlook Web Access user interface. To reach public folders by using an Exchange 2007 server that is running the Client Access server role, you must use the /public virtual directory. For example, if you ordinarily log on to Outlook Web Access by using the URL https://fourthcoffee.com/owa, you would reach your organization's public folders by using the URL https://fourthcoffee.com/public.

For improved public folder performance in Outlook Web Access and improved performance when making Availability service requests:

• Set the default public folder database for all Exchange 2007 mailbox stores in an Active Directory site to an Exchange 2007 public folder store in the same site.
  
• Replicate all Exchange 2007 system folders in an Active Directory site to an Exchange 2007 public folder store in the same site and consider replicating all public folder content.
  

Note:

By default, if the Exchange 2007 server that is hosting the Client Access server role is also hosting the Mailbox server role, the /public virtual directory is not configured to use Secure Sockets Layer (SSL). If you have installed the Client Access role and Mailbox role on the same Exchange 2007 server and want the /public virtual directory to require SSL, you must configure the virtual directory to do this.

Public Folders is fully supported in Exchange 2007 Service Pack 1 (SP1) and offers the following features:

• Full access to Public Folders from Outlook Web Access without having to use the /public virtual directory
  
• Full access to Public Folders on Exchange 2007 Mailbox servers without having to keep an Exchange 2003 mailbox server available for Public Folder access from Outlook Web Access.
  
• Public folders on an Exchange 2003 mailbox server are still available to Exchange 2007 mailboxes through Outlook Web Access.
  

Interoperability

The type of mailbox that is being used to access a public folder through Outlook Web Access determines the behavior of the public folder user interface (UI) in Outlook Web Access.

When Outlook Web Access accesses public folders from an Exchange 2007 SP1 mailbox, Outlook Web Access first tries to connect to an Exchange 2007 SP1 public folder store. If no Exchange 2007 SP1 public folder database is available, the Outlook Web Access server next tries to connect to an Exchange 2003 public folder store. When it connects, the user will see the public folder by using the Outlook Web Access 2003 UI. 

Exchange 2003 public folders will be available to Exchange 2007 mailboxes only if the following conditions are true:

• The server that is hosting the Client Access server role must not be hosting any other Exchange 2007 server roles.
  
• The /public and /owa virtual directories must have the same SSL setting.
  
• The /public virtual directory has not been renamed.
  
• SSL is disabled on the home public folder server that is assigned to the user's mailbox.
  

If the mailbox is identified as an Exchange 2003 mailbox, Outlook Web Access will try first to find an Exchange 2003 public folder store. If no replica is available on an Exchange 2003 server, the user will be unable to access public folders.

Exchange 2000 mailboxes cannot access public folders on Exchange 2007 servers.

Note:
The mailbox type is identified by the version of the server that is set as the preferred public folder server for the mailbox database, not by the version of the server that hosts the mailbox.

For more information about public folders, see the following topics:

• Understanding Public Folders
  
• Managing Public Folders
  
• Set-MailboxDatabase
  

For more information about Outlook Web Access features and virtual directories, see the following topics:

• Client Features in Outlook Web Access
  
• Managing Outlook Web Access Virtual Directories in Exchange 2007
  

For more information about how to help secure Outlook Web Access, see the following topics: 

• Using ISA Server 2006 with Outlook Web Access
  
• How to Configure Outlook Web Access Virtual Directories to Use SSL