The term “forced proxy” is equivocal. This means both “intercepting proxy” because it filters all traffic on the gateway is only available to Internet and its exact opposite, “non-intercepting proxy” (because the user is forced to configure a proxy to access the Internet) .

Forced proxy operation is sometimes necessary due to problems with the interception of TCP connections and HTTP. For example, the interception of HTTP requests can affect the usability of a proxy cache can greatly affect certain authentication mechanisms. This is mainly because the client thinks he is talking to a server, so request headers required by an agent can not be distinguished from headers that may be required by an upstream server (esp authorization headers). Also the HTTP specification prohibits caching of responses to the request contained an authorization header.