My company has a client with remote locations across the country exchanging files with a central system. In order to minimize the risk of viruses, they still insist that the remote computers can not be connected to a local network or the internet, and they use dial-up to transfer the files.

Other clients with another product use sneaker-net to transfer files between systems. While not quite as secure because some viruses can be transferred to the media along with the desired file, it still limits exposure because of the physical transfer method.

(Maybe they should run OS/400 instead of Winders, but that's just a geeky server prejudice.)

Most systems can have adequate security, but it's expensive and time consuming to implement proper physical and logical security. Within the last year, the military has prohibited the use of USB drives on their systems.