Methods, signals, devices, and systems are provided for using proxy servers to transparently forward messages between clients and origin servers if, and only if doing so does not violate network policies. In some systems, a transparent proxy uses a combination of standard-format HTTP commands, embedding...http://www.google.de/patents/US7954144?utm_source=gb-gplus-sharePatent US7954144 - Brokering state information and identity among user agents, origin servers, and proxies
