Without setting up your browser to use a caching proxy manually, how do you force HTTP requests passing through a caching proxy? Describe the processes of setting up an active and a passive connection...

Without setting up your browser to use a caching proxy manually, how do you force HTTP requests passing through a caching proxy?

Describe the processes of setting up an active and a passive connection for FTP, respectively (including the command and parameters used). Assume that the control connection has already been established on port 21.