Block HTTP_X_FORWADED_FOR by iptables

Question

I have to 2 servers: - front - backend

Front server is a proxy to backend I have no access to front server.

So..

How i can block ip address in backend, if i see real ip only in http_x_forwaded_for header?

Answer 1

I think you can not.

You can:

• block the IP on front server - this is the way you must do it.
  also is probably good idea to firewall backend server from all IP addresses but front server and probably your administrative IP's.
• use webserver on backend to block based on the header.
  on Apache this can be done with .htaccess.
• on backend, use the scripting language (PHP or whatever) to show blank page based on the header.