A question about java web apps and X-REAL-IP header

Question

I\'m setting up a demo of a project for a client. On my server I have a lot of sites built with different technologies that are running under different servers on different port

Answer 1

That depends on what you mean by "real request IP". If you're talking about the value returned from request.getRemoteAddr() then yes, it's possible.
The way to do that would be to set up a servlet filter in your web application that would intercept all URLs (or only the ones for which you want X-REAL-IP returned) and have that filter wrap incoming request into a descendant of HttpServletRequestWrapper which will override getRemoteAddr() to return X-REAL-IP value.