request.refralurl, is it safe and consistent. in reverse pro

Question

hi,

I have configured my website on iis "localhost:8087"

now I have used a reverse proxy or proxy server ( nginx on localhost:88) which in turn calls localhost:8087.

for this change i have to prefix the location attribute of nginx to request.redirect in asp.net.

ex

with out nginx i was using Response.Redirect("Default.aspx", false);

then with Nginx I have to use Response.Redirect("/ptk/jbl1/Default.aspx", false);

my problem is how to get localhost:88/ptk/jbl1, so that I can append appropriate parts where every required.

yours sincerely