my understanding was that proxies create a new TCP connection to a remote website for every client connection. Recently I got a tcpdump (sorry, cannot share it here) with a single TCP connection between the proxy and a remote website and several GET requests from two different users (both User-Agents and cookies are different). It looks like a pipelining (https://en.wikipedia.org/wiki/HTTP_pipelining). Can this behaviour confuse the web server? Does a server require X-Forwarded-For or similar header to disqungish such requests?
here is a "follow tcp stream" output excerpt:
GET /a HTTP/1.1 Cookie: JSESSIONID=123 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko Host: example.com Via: proxy1 Cache-Control: max-age=0, max-stale=0 Connection: keep-alive HTTP/1.1 304 Not Modified Date: Tue, 10 Dec 2018 01:01:01 GMT Content-Type: text/plain;charset=utf-8 Cache-Control: no-cache Pragma: no-cache GET /b HTTP/1.1 Cookie: JSESSIONID=456 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/533.11 (KHTML, like Gecko) Chrome/81.0.2.3 Safari/533.11 Host: example.com Via: proxy1 Cache-Control: max-age=20000, max-stale=0 Connection: keep-alive HTTP/1.1 304 Not Modified Date: Tue, 10 Dec 2018 01:01:01 GMT