KS AntiDDOS script. It works as fast as PHP allows it. All the data is stored in the shared memory, so there is no disk operation.(besides of reading the script).You can limit visitor`s hits for the time you need. For example, you can limit 10 hits from an IP in 5 seconds.All excessive hits will be replyed with 503 Service unavalable HTTP status.By default, my script uses C class net blocking. That means that it considers alls IP like, for example 11.22.33.*as single IP 11.22.33. and blocks it when it`s activity is too high. This significantly improves DDOS blockingfrom infected networks.KS AntiDDOS operates only in HTTP channel, there are many other DDOS techniques, but HTTP flood can get yor server down with considerable less botnet capacity.Script is free. You are welcome to download it and use.
