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.