Maximum download size

[mize.williams]

Hi, guys

I've installed squid and squidGuard to try and limit the users download size. I configure it on the Traffic Mgmt tab. Now after testing the feature I found out that it works on some sites and not all.
For example it blocks downloads from zippyshare but from gns3.com or omerta.is it lets them through.

the squid "site says downstream caches probably can not detect a partial reply. if there is no content-length header, so they will cache partial responses and give them out as hits.  You should NOT use this option if you have downstream caches". can this be the cause?

Can someone point me to the reason and a solution for this?