the best methode is to find out where a hacker lives and try too kill him.
(becouse there isn't any other way to stop them 100%)
sry for my bad english.
OK but then i think the server could be programmed in a way that speedhacking is impossible.
This will only work in a latency free environment. When you do take packet latency into account however, you also have to factor in a confidence range of probable variations of the rate of change of the positions of the players. However, as the latency increase, the interval of the variation increases multiple folds, and as there is no simple direct correlation between the two variables, a simple rate-checking system will only be effective for <~80 ms latency.