In order to block a specific file type without blocking everything by extension, several conditions need to be filled. Let's look at the following example using the Perl scripts file type and its .PL extension.

1. Create a new block security rule.
2. In the “True Content Type” condition, select text file. (Perl scripts are downloaded as text files.) Please see the picture below.
   
   
   
   
   
   
3. In the File Extension condition, select PL extension. This ensures that the rule will be enforced only if the file has a Perl script content type and also .PL extension. Please see the picture below.