Implementing Calendar Interoperability


For the purposes of this section, it is assumed that all non-Exchange and Exchange users work with Outlook 2003. As a MAPI-based client, Outlook can be used in a variety of messaging configurations with Exchange, Microsoft Mail for PC Networks, IMAP4, Lotus Notes, Novell GroupWise, HP OpenMail, AT&T Mail, CompuServe, and other messaging systems for which a MAPI transport driver is available.


Microsoft only supports the IFB publishing feature when Outlook is configured for the Internet Mail Only mode.

You must complete the following steps to share free/busy information using the IFB publishing feature:

  1. Configure Outlook to publish free/busy information   To publish free/busy information, you must enable the option to publish and search for free/busy information using the Internet Free/Busy service or publish free/busy information at an internal location. You can find corresponding configuration options in Outlook by clicking Tools, clicking Options, clicking Calendar Options on the Preferences tab, and then clicking Free/Busy Options. If you publish the free/busy information on an internal server, type the fully qualified path to the server in the text box that becomes available when you select the Publish at My Location option. You can specify the location in HTTP, FTP, or FILE URL format. If you are using an FPT server with Anonymous Login disabled, you must specify the user and password information in the FTP URL as follows:<SMTP domain>/<SMTP alias>.vfb

    User is the user name of the account and Password is the password associated with the account. SMTP domain corresponds to the user's SMTP domain name, and SMTP alias refers to the user's e-mail address within the SMTP domain. Free/busy files have an extension of .vfb.

    You should choose the file name and path to the file for publishing free/busy information carefully, so that users do not need to maintain a specific search location for each individual user. Outlook supports the %NAME% and %SERVER% substitutions in the search location. In an SMTP address, Outlook replaces %NAME% with all of the characters before the at sign (@) and replaces %SERVER% with all of the characters following the @. Because the name portion of an e-mail address is guaranteed to be unique within an SMTP domain, this way of organizing .vfb files prevents naming conflicts. Ensure that the folder structure exists before you configure the IFB publishing feature in Outlook. Figure 1 shows the recommended folder structure for two SMTP domains.

    Figure 1   Publishing free/busy information organized by SMTP domain


  2. Set the global free/busy search path in Outlook   If all of your users store their free/busy information on the same server, you can set the search path for this information globally for all contacts. You must specify only the fully qualified path to the location where you want to search for the free/busy information in the Search locations text box in the Free/Busy Options dialog box. If you followed the recommendations for the free/busy folder structure, you can specify the search path using the %NAME% and %SERVER% substitutions. For example, in Figure 1, the global search path would be as follows (the structure is similar for HTTP and FTP URLs):


    You can also set the search path specifically for each SMTP recipient, which is useful if the location of free/busy information varies by recipient. First, create a contact object for the recipient in your Contacts folder. You can then specify the path to that recipient's .vfb file in the Address text box in the Internet Free-Busy section on the Details tab.

  3. Implement an ASP.NET-based solution so that Exchange users can parse .vfb files   As mentioned earlier in this topic, Exchange users cannot access published free/busy information for SMTP recipients if mail-enabled user accounts or mail-enabled contacts exist for these recipients in Active Directory. To provide Exchange users with access to the free/busy information, you can implement an ASP.NET application published through IIS on the IFB publishing server. You can use the TreeView Web control to display the SMTP recipients organized by SMTP domains. For more information about the TreeView Web control, see "Using the TreeView IE Web Control" (