Denial Of Service/ DDOS (Legal, on private server)

What would be the best windows/mac (I have both) code (other than “ping IP -t -l #”) to effectively remove an IP from a server?
I am hosting a website and would like an effective kick system to stop dynamic IPs on the vote of other users.

The code should be executable with command prompt or it’s MAC equivalent. Thanks

FYI for those who don’t know, it’s called Terminal.