Unix tip: Password complexity for users [Video]

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On older Solaris systems, you would only see a few tunable parameters for controlling passwords. MINWEEKS determined the number of weeks that a user was required to keep his password. MAXWEEKS determined how many weeks could go by before he was forced to change it. And PASSLENGTH, of course, determined the minimum number of characters a password had to have to be accepted by the system. These settings limited the time that a user could keep a password and potentially kept him from changing his password on expiration and immediately changing it back to its original setting.

These settings are stored in several fields of the /etc/shadow file. The record below, for example, shows a password which just recently expired. It was last changed a little over a month ago (date), but was set to expire after 28 days (max). The user was prevented from changing his password within two weeks of setting …