Because of the large number of client requests needed to actually make a proxy caching server pay off in the way of speed versus just routing the requests directly to the content servers, it has quickly become popular for smaller organizations to use them more for their additional features, such as controlling access to content servers.

The decision to force your clients to use the proxy server for FTP and HTTP services can be implemented in many ways. The easiest way may be to implement some firewall rules.
address-suppressed