Consider the following scenario:
In Microsoft Lync Server 2010 Control Panel, you configure a file filter to block URLs that contain the .exe extension.
You select the option Enable URL filter and the Block URLs with file type extension option.
You set the Hyperlink prefix setting to Send warning message.
After you commit the changes, a Lync 2010 user tries to use an instant message to send a URL that contains an .exe extension to another Lync 2010 user. The URL also contains a hyphen or a colon. For example, the user tries to send http://www.thephone-company.com/app.exe or http://example.com:8080/app.exe in an instant message.
In this scenario, the instant message is not blocked by the URL filter.
This issue occurs because the special characters are handled incorrectly by the URL parser.
To resolve the issue, install the following cumulative update:
2737915 Description of the cumulative update for Lync Server 2010: October 2012
For more information about how to configure filtering for instant messaging, go to the following Microsoft website: