The situations you're describing don't require you to "simulate valid
popular protocols" at all. You can accomplish your objective by
*actually*running* those protocols, then abuse the endpoint in the
For example, acutally surf the web, while performing a syn flood attack
on the machine. No need to simulate, just use your browser of choice
to load some web pages!
Some of the tests you describe (out of order segments / ip
fragmentation) will require you to put a broken network in between the
TCP endpoints. There's a great (and free) broken network called
It will allow you to drop or delay packets at will.
For fragmentation, I imagine you'll have to fiddle with the NistNet
In any event, you're looking to abuse traffic, but there doesn't seem
to be a need for a traffic simulator.