I'm looking for a good multi-purpose proxy server for the sole intention of self-education. Preferably, ones that do both packet filtering and caching. I've got myself an old P3 box that I've installed FreeBSD in and have spent a good two weeks tinkering with ipfw packet filter software among other things. I think it's about time that I upgrade a notch further with proxies.
I've checked Squid but at this point, I would prefer an all-rounder.
A few additional queries :
1) Why do *most* if not all, streaming packets (videos, mp3s etc.) travel over UDP not TCP? I notice that it has something to do with UDP's stateless protocol but I couldn't make that one out.
2) As in (1), why *in general* does a UDP connection is considered a security issue?
3) This may sound a little stupid but how do a DoS attack happen?
For the knowledgables, I hope you can contribute something to this thread.
Thank you in advance.