When I look at /etc/shadow I see several entries that look like this:username:**___________:::::::What does the **___________ mean? That is where I should see the password hash.
What does **___________ mean in /etc/shadow?
password;shadow
A password field that starts with * means the corresponding user is not allowed to login.  This is generally used for system accounts, such as mysql, mail, apache, etc.However, if the entry is literally ending with :::::::, this means the corresponding user is a NIS / NIS+ account.