What do configuration files define in Linux systems?
System-wide account expiration and password aging rules.
Why are configuration files used?
To enforce security policies requiring periodic password changes or account deactivation.
Which file contains default password aging settings?
/etc/login.defs
What does PASS_MAX_DAYS do?
Sets the maximum number of days a password is valid.
What does PASS_MIN_DAYS do?
Sets the minimum number of days before a password can be changed.
What does PASS_WARN_AGE do?
Sets the number of days before password expiration to warn the user.
Give an example of setting max password age.
PASS_MAX_DAYS 90
Which file contains user-specific account information?
/etc/passwd
How is the expiration date stored in /etc/passwd?
As the number of days since January 1, 1970 (epoch time) in the last field.
Example of viewing /etc/passwd content?
cat /etc/passwd
Example line from /etc/passwd with expiration?
alice:x:1001:1001:Alice User:/home/alice:/bin/bash:1680744000
What does 1680744000 represent?
The expiration date in epoch time.
Is modifying /etc/passwd directly recommended?
No, it is possible but not recommended.
Which command manages password aging and account expiration per user?
chage
What does chage allow?
Setting password expiration dates and account inactivity periods for individual users.
Example command to set account expiration?
sudo chage -E 2025-12-31 alice
What does this command do?
Sets Alice’s account to expire on December 31, 2025.
What happens after account expiration?
Login will be denied unless changed.
