How to restrict access based on user ip address for apache behind netscalar

Question

I tried to use Require ip XX.XX.XX.XX . However, this not does work as REMOTE_ADDR contains the NetScaler's ip not the client ip. Is there a way NetScaler can set REMOTE_ADDR to client ip address? NetScaler sends client ip in HTTP_CLIENT_IP. How can I set it to REMOTE_ADDR in apache config?