Hi Bluce
I had the same problem and I was advised two options by a friend of mine :
1) Quick and dirty method is to block the IP in IPChains of your system, but that wont relieve the system fully as request would still be coming but now your system would be dropping the request from that IP.
2) Other method is to get that IP blocked @ gateway, that wud completely relieve ur system from that IP
Hope it helps
