I need a program that runs on our router(a linux box) that can watch all our four segments and send out an alert(eg. an email or something like that) if someone starts to flood the network with e.g. ping-flood,winnukes,syn-flood and so on.

We have to use it on a party network, my company has specialized in delivering network for computerpartis.

And we found that flooding attacks has come very populare so we need som protection.