Just think; you have a gazillion PCs, all with some combination of serial, parallel, infrared, Firewire and USB ports. Not to mention 802.11 wireless cards, writable CD drives, floppy disks and hard disks. Think about it; each port and device is a potential major security hole.

Now in your network environment just consider what one of your users with an empty iPod, access to a USB port and bad intentions could get away with . . . chills you to the marrow, doesn't it?