Need advice about protecting ddos via iptables and whitelisting. Currently I launched my gameserver and am fighting against a massive attack of botnets. Problem was solved by closing all ports on my gameserver linux machine and shipping game.exe with injected c++ socket client. So basically only gamers who launch my game exe are being added to firewall iptables via the socket client that is provided in the game exe. If some ddosers still manage to get inside and ddos then my protection is good enough to handle attacks from whitelisted ips from inside. Now I have another problem. Lots of players have problems and for some reason shipped c++ client fails to connect to my socketserver. Currently my solution was to provide support in all contact channels (facebook,skype,email) and add those peoples ips to whitelist manually. My best solution would be to make a button in website which you can click and your ip is whitelisted auromatically. However if it will be so easy then botnets can whitelist themselves as well. Can you advice me how I could handle whitelisting my players through web or some other exe in a way that it cant be replicated by botnets?