NetHogs is a small 'net top' tool. Instead of breaking the traffic down
per protocol or per subnet, like most tools do, it groups bandwidth by
process. NetHogs does not rely on a special kernel module to be loaded.
If there's suddenly a lot of network traffic, you can fire up NetHogs and
immediately see which PID is causing this. This makes it easy to indentify
programs that have gone wild and are suddenly taking up your bandwidth.