g1smd - 6:56 am on Apr 12, 2013 (gmt 0)
A redirect is an instruction from the website to the browser. It tells the browser to make a new request for a new URL.
If you want to access a site "but the URL stay the same" you need something other than a "redirect". You need an internal rewrite if the two sites are on the same server or a proxy passthrough if not.