How to Block X forwarded-for IP in nginx

Thanks all for help. I found solution for this issue. Maybe there is some bug in nginx due to which i found double IP in $http_x_forwarded_for but with the help of real_ip module now i able to block IP using $remote_addr header. By including below code in my vhost conf now i get client IP in $remote_addr header.

set_real_ip_from 0.0.0.0/0;
        real_ip_header X-Forwarded-For;
        real_ip_recursive on;

set $allow true;
if ($remote_addr ~ "180.179.") {
     set $allow false;
}
if ($remote_addr ~ "199.47.") {
     set $allow false;
}
if ($allow = false) {
     return 403;
}