Blocked File Types and Extensions

Mailprotector blocks high-risk extensions from being relayed inbound or outbound through our security layers.  If you/your users attempt to send a banned extension, they will receive the following response (bounce/NDR) with the following explanation and corrective actions.

A file you sent was blocked by CloudFilter™

You are trying to send an email message with a file attachment to a recipient protected by CloudFilter email security from Mailprotector®. The file attachment that you are trying to send contains a three-letter extension which makes this file "executable."

Computer viruses are often spread as programs attached to email messages. These messages usually trick the recipient into clicking on the file and "executing" the program. However, some are able to automatically execute themselves when an email message is merely previewed by the recipient. Because of this, the following file extensions are automatically blocked by CloudFilter:

Blocked Extensions

.ade Access Project Extension
.mdb Access Database
.adp Access Project file
.mde Access file
.bas BASIC Program
.msc Common Console Doc (Win2k)
.bat DOS Batch File Script
.msi Installer Program
.chm Compiled HTML file
.msp Windows Installer Patch file
.cmd 1st Reader External Command Menu
.mst Windows Installer Transform file
.com Command file (Program)
.pcd P-Code Compiled Test Script
.cpl Control Panel Module
.pif Program Info file (Win 3.1)
.crt Certificate file
.reg Registration file
.exe Executable file (Program)
.scr Screensaver
.hlp Windows Help file
.sct FoxPro Form
.hta HTML file
.shs Shell Scrap file
.inf Package Information file
.url Internet Shortcut file
.ins Install Script
.vbs VisualBasic Program
.isp Sign-up file (X-Internet)
.vbe VisualBasic Related
.jsp JavaScript
.wsf Windows Script Component
.lnk Shortcut file (Windows)
.wsh Windows Script file
.wsc Windows Script Host Settings file
.js JavaScript


Question: How can I send my message? 

Answer: The first option is to rename your file attachment. For example, you could rename your attachment to "filename.txt" with instructions in the body of your message as to what the appropriate extension should be. Another option is to compress your file(s) with an easy to use file compression utility.

Question: I'm having trouble with blocked attachments in Outlook also. How can I fix that?

Answer: Similar to the protection provided through CloudFilter, Outlook blocks dangerous file types and extensions. Visit Microsoft's knowledge base article on blocked attachments for more information.


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