What is the use of “Proxy-agent” header?

Question

Does anyone know the usage of "Proxy-agent" response header ?

Answer 1

Proxy-Agent: is a non-standard header - it is not defined by any HTTP RFC. As a result, it should technically be X-Proxy-Agent:. If you want a definition of anything about the way that HTTP works, RFC 2616 is your bible.

Because it is non-standard, there is no definite answer to this question. At a guess, from the name of the header, it would contain the name of the HTTP proxy software that is handling the request on behalf of the User-Agent:. But, because it is non-standard, what it actually means could be something completely different.

What I can tell you is that, because it is non-standard, it is not likely to be pertinent to the way you handle the request - although it likely informs you that there is at least one proxy somewhere along the route between the client and the server.