How to Control Web Beacon and HTML Form Filtering for Outlook Web Access
Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-08-22
This topic describes how to use the Exchange Management Shell to disable Web beacons and HTML forms on Microsoft Office Outlook Web Access in Microsoft Exchange Server 2007. A Web beacon is a file object, such as a transparent graphic or an image that is put on a Web site or in an e-mail message. Web beacons are typically used together with HTML cookies to monitor user behavior on a Web site or to validate a recipient's e-mail address when an e-mail message that contains a Web beacon is opened. Web beacons and HTML forms can also contain harmful code and can be used to circumvent e-mail filters.
By default, Web beacons and HTML forms are set to UserFilterChoice. This blocks all Web beacons and HTML forms but lets the user unblock them on individual messages. An administrator can use the Exchange Management Shell to change the type of filtering that is used for Web beacon and HTML form content in Outlook Web Access.
Web beacon configuration is set on a per virtual directory basis for each Outlook Web Access virtual directory in your organization.
For more information about Web beacons, see Managing Outlook Web Access Advanced Features.
To perform the following procedure in the Exchange Management Shell, the account you use must be delegated membership in the local Administrators group for the target server.
For more information about permissions, delegating roles, and the rights that are required to administer Exchange 2007, see Permission Considerations.
Run the following command to block all Web beacon and HTML form content on an Outlook Web Access virtual directory named owa in the default Internet Information Services (IIS) Web site on the local server:
Set-OwaVirtualDirectory -identity "Owa (Default Web Site)" -FilterWebBeaconsAndHtmlForms ForceFilter
The possible values for FilterWebBeaconsandHtmlforms are as follows:
UserFilterChoice By default, this value blocks Web beacons and HTML forms, but lets the user allow Web beacons and HTML forms on individual messages.
ForceFilter This value blocks all Web beacons and HTML forms.
DisableFilter This value allows Web beacons and HTML forms.
Note: Both UserFilterChoice and ForceFilter cause the user to be presented an option to unblock blocked content on individual messages. If the parameter has been set to ForceFilter, the content will remain blocked regardless of the user's choice.
For more information about syntax and parameters, see Set-OwaVirtualDirectory.