A Network Security Class?

eap asks: "Some friends of mine and I are creating a Network Security course to take this summer. We have discussed the idea, but so far haven't decided what the class should entail. We were thinking of running exploits against several OS's, and then trying to plug the holes. Could anyone recommend a 'syllabus' for how such a class might go?" This is a good idea, but they need to flesh out that syllabus a bit more. Running exploits and plugging the holes is one thing, but that's not all there is to securing your LAN, is there? For one thing, it leaves out -internal- network security..not all threats to a network exist on the outside.