http://www.rfc-editor.org/rfc/rfc1919.txt
RFC 1919: Classical versus Transparent IP Proxies, M. Chatel1996-03-01T23:00:00-00:00This document explains "classical" and "transparent" proxy techniques and attempts to provide rules to help determine when each proxy system may be used without causing problems. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.