Proxy is defined by for our use as an Entity authorized to act on behalf of another. (Which is Delegation)

So we could say a permission has been delegated by an Entity to the Proxy

Proxy Servers are probably the most often used instances of a Proxy for most of our purposes.

Proxy is an Observer#

Proxy and therefore Proxy Servers are by definition an Observer and a potential Man-In-The-Middle

RFC 2616#

RFC 2616 defines Proxy as an intermediary program which acts as both a server and a client for the purpose of making requests on behalf of other clients.

Requests are serviced internally or by passing them on, with possible translation, to other servers. A proxy MUST implement both the client and server requirements of RFC 2616.

A "Transparent Proxy" is a Proxy that does not modify the request or response beyond what is required for Proxy authentication and identification.

A "non-transparent proxy" is a Proxy that modifies the request or response in order to provide some added service to the user-agent, such as group annotation services, media type transformation, protocol reduction, or anonymity filtering. Except where either transparent or non-transparent behavior is explicitly stated, the HTTP Proxy requirements apply to both types of proxies.

More Information#

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