What is the difference between Connection and Proxy-connection in HTTP header?
http, http-headers, http-proxy, proxy
Solution
The `Connection` header is a standard header defined in the HTTP 1.0 and 1.1 specifications (RFC 2068 and RFC 2616) for maintaining keep-alive behaviour on an HTTP connection.
`Proxy-Connection` was an experimental header created by the Netscape developers to do similar things due to a misunderstanding about when `Connection` header could be used. It has never worked properly and is ignored by many of the common HTTP systems in existence today. When it does work as designed there is no difference between the two.
Problem
What is the difference between `Connection` and `Proxy-Connection` in HTTP header? Is the `Proxy-Connection` field added by the proxy? Or the client and server? What will the proxy, client or server do after receiving a header with these two fields with value keep-alive and close respectively?