Comment: Re:Best be a Coward for 5 minutes........ (Score 1) 217
A successful DDOS attack makes actual, valid, requests to the victim host. If it is a web browser, then it makes actual HTTP requests, possibly to the home page, possibly taking a random URL off that home page, in the same domain, and crawling the web site. Simply replying with an Ack isn't going to do squat. There are services out there that can scrub the requests for you. I'm not going to mention the name of the company, but you can research it if you want. Basically, once you sign up traffic normally goes to your site. However, if you are attacked they can use BGP to make your traffic go through their systems, and they scrub the traffic using proprietary methods, and only send clean non-DDOS traffic to your site. There are other things you can do also, if you have the right gear. You can inject a HTTP cookie if you get more than x requests from a particular IP address within y seconds, and then any future requests may get dropped (if you have a complying web browser or HTTP stack on the other end). Or, you can just keep a list of IP's that appear to be infected and drop the traffic if it is from those IP addresses. That's what is behind Cisco's and TippingPoint's, and just about any other decent IPS vendor's "reputation services" or whatever they brand it as. There is a lot you can attempt to do about DDOS, but "simply replying with an Ack" isn't a good one.