Re-Route a specific IP address through VPN to a defined server
I have a iPhone connected to my OpenVPN server which works fine. Now I want that when the iPhone tries to reach a specific IP that this traffic is routed through the VPN tunnel and on the OpenVPN server I want to re-route this IP address to the server itself. I can define in the iPhone Configuration Utility that it should open a VPN connection when the specific IP address is called. In the OpenVPN configuration file I then can configure that all traffic should go through the VPN tunnel. My problem is, how can I re-route the specific IP on the VPN server to the server itself.
For what is this all for? I have a siri proxy on that machine. Since iOS 6 the iPhone uses both, wifi and cellular to ask for the apple server with a DNS lookup. I can not prevent the lookup over cellular, but I can (hopefully) tunnel all traffic through my VPN. So that when the iPhone made the lookup for kryten.apple.com and tries to access it via IP address that this traffic goes through the tunnel and on my VPN server I define a rule so that the IP from kryten.apple.com which I know is rewritten to the private IP of my server.
How can I achieve this? iptables?
Thanks in advance for your help.