Nginx replace REMOTE_ADDR with X-Forwarded-For

Question

I am quite new to Nginx, and it seems all so confusing. I have my server setup perfectly, but the problem is, since my server is protected using a HTTP proxy; instead of log

Answer 1

$http_x_forwared_for might contain multiple ip addresses, where the first one should be the client ip. REMOTE_ADDR should only be the client ip.

So by using regex in your nginx.conf, you can set REMOTE_ADDR to the first ip of $http_x_forwarded_for like so:

  set $realip $remote_addr;
  if ($http_x_forwarded_for ~ "^(\d+\.\d+\.\d+\.\d+)") {
    set $realip $1;
  }
  fastcgi_param REMOTE_ADDR $realip;