Okay so I have set up 2 computers on a router not connected to the internet. With some custom firmware I was able to set up the router to cap limited bandwidth traffic to and from each computer to the other. I made the downstream about twice as much as the upload limitation (1 megabyte per second download limit, and 500 kilobyte upload limit).

I want to simulate a DoS attack from one computer to the other. How would I go about spoofing like a dozen IP address to flood the other? Otherwise I can only ping a few 65,535 byte size packets every second or so which isn't enough to hardly do anything. Obviously I don't have any malware-spawed zombie botnets available at my disposal since this is a closed/isolated network, so what other options are there? Sorry if my networking knowledge seems a bit elementary.