Looking for some program that will do this...

["Dan Lockwood" <dlockwood () shastacoe org>]

Hi all,
 
I'm looking for a program that can generate "real" looking traffic.  It should be able to send TCP/UDP traffic to a 
large set of hosts (thousands), send traffic to random or semi-random ports and send packets/datagrams that are of 
random/semi-random size.  Ideally it should run on windows or some sort of Perl script would be fine.  Anyone have any 
ideas or should I dust off my programming books?
 
Thanks,
Dan