Besides disabling items, what is the best way to prevent duplication glitches on tekkit servers?

Solution 1:

There are too much bugs in tekkit to prevent this, and it would be nearly impossible to program a plugin which checks if someone exploits any single one of these many bugs. You could make a plugin which warns you if someone gets very much items in a very short period of time, but this would only prevent excessive buguse. Against the flyhack, you could use this mod, which should prevent flyhacking without disabling the fly ring.