Req: simple packet flooding tools

[Jim Breton <jamesb-vulndev () ALONGTHEWAY COM>]

Looking for suggestions on what tools are good for performing simple
packet floods.  TCP/UDP/whatever.  Need some utils for testing similar
DoS attacks against several machines running different OSes on comparable
hardware.

Preferably something that will compile on Linux or OpenBSD (Win32 is
fine too, as a last resort).

Thanks.