Block Additional Attachment Types

This article describes how to configure Microsoft Outlook to block attachment file name extensions that Outlook does not block by default. If you use Outlook in a Microsoft Exchange environment, you can configure the server to block certain attachment file name extensions by using the Outlook E-mail Security Administrator Package.

Choose between two options:

Level1Remove -- slow down access to the zip by forcing users to save them to the hard drive before opening them.

Level1Add -- treat *.zips like *.exes to prevent access to them.

* Level1Remove

To Add file types to Level1Remove key:

1. Run Regedit, and go to this key: HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security (change 10.0 to 9.0 for Outlook 2000 SP3 or to 11.0 for Outlook 2003, 12 for Outlook 2007)

2. Under that key, add a new string value named Level1Remove.

3. For the value for Level1Remove, enter a semicolon-delimited list of file extensions. For example, entering this:

.zip;.mdb;.url

would force you to save Zip file type and unblock Microsoft Access files and Internet shortcuts.

* Level1Add

To Block file types using the Level1Add key: To add additional attachment file name extensions types that you want blocked, you must add the Level1Add key to the registry. To do this, follow these steps.

1. Run Regedit, and go to this key:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security (change 10.0 to 9.0 for Outlook 2000 SP3 or to 11.0 for Outlook 2003, 12 for Outlook 2007)

2. Under that key, add a new string value named Level1Add.

3. For the value for Level1Add, enter a semicolon-delimited list of file extensions. For example, entering this:

.zip

would treat the Zip file type like exe's and block access to them.