Is there a way to prevent modded clients (flying, etc)

Just wondering.

I have like 3 users in my server with modded clients just flying around.

Not really a huge deal, but it kind of undermines the whole permissions plugin...

 

I would also like to know, but maybe to allow certain client mods. I use the mod that gives you a little radar map in the upper left corner and it is very helpful

 

+1

 

AFAIK there is an API call in bukkit to get the highest block coordinate for a given position. You could check at an regular interval if any player is, let's say, 20 blocks or higher above this location. If they are, they must be cheating/flying. You can make this more sophisticated so that it correcly handles falling from cliffs etc. by checking over several intervals if they move in the horisontal plane.