Your first barrier against intruders is user passwords and IDs. Operating systems like Microsoft's Windows 95 or NT and Novell's NetWare have built-in password and ID functions. Although they can be somewhat easy to get around, they serve as a minimum level of defense to restrict unwanted access into computer systems, databases and files.
Instruct employees to change their passwords frequently, refrain from sharing them with others, and stop keeping them on Post-it notes stuck to their computers. Choose passwords with at least seven characters; many programs will let you establish ones with dozens of characters. Try to mix lowercase and uppercase letters, avoid using any character more than once, and incorporate punctuation, numbers and symbols. Stay away from obvious passwords like a spouse or child's name, birthdates and other personal information such as social security or telephone numbers.