Today i was going through some of security guides written on linux .
Under shadow file security following points were mentioned.
1)The encrypted password stored under /etc/shadow file should have more than 14-25 characters.
2)Usernames in shadow file must satisfy to all the same rules as usernames in /etc/passwd.
3)password for application Username should display * if username is not locked.
4)If a user is locked it should be displayed as ! as the first character in second field of shadow file.
Confusion for point 1 and 2:
Now i m confused as why the encrypted password should be more than 14-25 characters.
Also what rules to satisfy How to check it?
Confusion for point 3 and 4:
There are lot of users with * as second field i guess they are not locked but according to 4th point there are lot of users with ! as first characters.
How would i check whether they are actually locked or not.
I m posting the output of /etc/shadow and /etc/passwd files for the account.