[Dovecot] Settings for authentication without an extra password file

Hello, I'm new to dovecot, and, due to having an older version of an OS installed on a test server, I'll be using an older version of dovecot (dovecot-1.0-1.2) to provide IMAP services.

On this wiki page (http://wiki.dovecot.org/BasicConfiguration?highlight=%28passwd.dovecot%29)

There are instructions for creating a separate dovecot password file:

echo "$USER:{PLAIN}password" > passwd.dovecot
sudo mv passwd.dovecot /etc

So, it appears that two password files will be needed, one for dovecot and one for regular system logins.

Is the statement above correct, or am I misreading something?

Is there a setting in dovecot.conf which will authenticate IMAP using /etc/password and /etc/shadow, without a separate dovecot password file?

========Keith