[Dovecot] Desperately need help ! a default dovecot.conf and/or Ubuntu 11.10 postfix/dovecot server configuration issue!

[D Chen]

When ungraded from Ubuntu 11.04 to 11.10, dovecot can't start successfully with lots of errors i.e.
"dovecot: doveconf: Warning: ... 'imaps' protocol is no longer necessary, remove it"...

At any rate, I want to setup a postfix(MTA)/dovecot(MDA) servers on Ubuntu 11.10, by following the Postfix installation and configuration instruction in Ubuntu Serverguide, in "1.4 Configuring SASL" section on page 190, after run "sudo apt-get install dovecot-common", it requires to edit the section of "auth default" and the "socket listen" option...,in the /etc/dovecot/dovecot.conf file, BUT my /etc/dovecot/dovecot.conf (only about 4k byes) CAN'T find the "auth default" "socket listen" !

I also checked into the /usr/share/doc/dovecot-common/dovecot/example-config, there is a
dovecot.conf, it's also about 4k size, and there is no such "auth default" or "socket listen" words can be found ! where is the default dovecot.conf file I can get a copy ?

BTW, there is the dovecot.conf.ucf file (what is this for?) which's about 50k and has the "auth default" and "socket listen" words there ! what is supposed the size for the /etc/dovecot/dovecot.conf ? i'm confused!

Thx.