What is SpamCheetah?
SpamCheetah is a LiveCD for spam control. It is useful when you run a mail server and you want to save bandwidth costs since SpamCheetah is a network level spam filter. SpamCheetah liveCD/liveDVD also comes with an option to install SpamCheetah to a hard disk(IDE/SCSI/SATA), USB pendrive, Disk On Memory module(DOM) or an external USB hard disk. However SpamCheetah is a Read Only OS instance and it never writes anything to persistent storage. This makes SpamCheetah incredibly fast and you also save on write cycles in case you run it off a USB stick. There is documentation on installing SpamCheetah on to a disk and installing SpamCheetah spam filter into your network here.