If your server is under DDoS or DoS attack, there is nothing to stop it. If you have a sophisticated hardware firewall such as Cisco 5520 ASA , you can minimize the attack to keep your server running and online for a longer period of time. To understand Internet attacks, go to: http://servertune.com/kbase/entry/64/my server has beed DDOSed 3 times this week and im gonna lose customers. so im just wondering if their is a way to find out which domain is being attacked, or how to stop it.