browser does not show x-forward-for header

 https://stackoverflow.com/questions/21595921/reason-for-browser-not-showing-x-forwarded-for-headers

X-Forwarded-For is not a standard request header as specified in RFC 2616 Section 5.3 that addresses the protocol standard request headers, which are (as specified in the RFC)

• Accept
• Accept-Charset
• Accept-Encoding
• Accept-Language
• Authorization
• Expect
• From
• Host
• If-Match
• If-Modified-Since
• If-None-Match
• If-Range
• If-Unmodified-Since
• Max-Forwards
• Proxy-Authorization
• Range
• Referer
• TE
• User-Agent

x-forward-for is auto added by browser, but also not reliable, as proxy safer can forward on behalf of client so the ip is proxy server(or vpn server) not actual client ip, (port fowarding)