[ILUG] /etc/shadow format

[Vincent Cunniffe]

What's the difference between * and !! for the password field in
/etc/shadow under Linux?

I've been poking around, and all of the standard system accounts
such as bin, daemon, etc have *, which translates as 'No Password
Set', and stuff such as squid or other brand-new users have their
entries set to !!, which translates as 'Locked Password'. Neither
can log into the system.

Anyone care to expound on the difference between these, and the
security reasoning behind it?

Regards,

Vin