System Administration Guide, Volume 1

Password Aging

If you are using NIS+ or the /etc files to store user account information, you can set up password aging on a user's password. Password aging enables you to force users to change their passwords periodically or to prevent a user from changing a password before a specified interval. If you want to prevent an intruder from gaining undetected access to the system by using an old and inactive account, you can also set a password expiration date when the account become disabled.