http-stats:
HTTP/1.1 Proxy-Connection header field

The Proxy-Connection field is NOT a standard HTTP header field and may not be supported by all clients.

It is quite common to find the Proxy-Connection header field in the wild. This is due to a mistake of programmers who implemented early version of HTTP software.

Unfortunately, this header has become quite common and supported by many HTTP agents. It was not needed to duplicate the functionality of the Connection header but somehow a few programmers misunderstood the specification.

You can read more on this topic following this link.


Common Proxy-Connection header values:

The non-standard "Proxy-Connection" header is only sent by:

NOTE: this header may be sent directly by the server software or from some third party application running on that server.

Sample Proxy-Connection web server response:

HTTP/1.1 200 OK
Content-Type: text/html; charset=UTF-8
Content-Length: 3335
Proxy-Connection: close
Date: Fri, 30 Jul 2010 17:01:50 +0000

<!DOCTYPE html PUBLIC "-//W3C//DTD ...
...
...

Other common HTTP headers

Other less common headers