i `ve blocked certain files with certain extension like "exe,Zip, Rar..." with MIME Http Defences Group
anyone know how to block it related to size
In the same Application Defenses screen you have been working with you will see that there is "maximum scan size" limit setting and you can configure the resulting action to be "reject" if the download is larger than the size specified.
In reality I wouldn't necessarily expect a Firewall to control the size of file downloads and would look to a specific web filtering/web access control solution, such as McAfee Web Gateway, to perform this kind of function.
thamks alot tring now ....