The ProxySG appliance and Cacheflow appliance do not cache content with certain values specified in RFC2616, Hypertext Transfer Protocol -- HTTP/1.1. 

As an example, a request URL is:

http://www.netflix.com/WiPlayer?movieid=60023597

A packet capture (PCAP) of the HTTP request follows: 

A PCAP of the response follows:  

Note the values of the cache-control fields. Netflix sets these values on their content in accordance with US federal copyright laws and the Intellectual Property Rights Center.