dovecot trouble

[mvp]

hello.

i installed postfix on my debian server, and that seems to work fine.

then i installed dovecot as my imap and pop3 server, but when i telnet port
110 and 143 it wont accept my login/pass created with useradd. as i
understood dovecot would automatically allow users on the system to login?

output from dovecot.conf

protocols = imap imaps pop3 pop3s
imap_listen = localhost
pop3_listen = localhost
imaps_listen = localhost
pop3s_listen = localhost
default_mail_env = maildir:/home/%u/Maildir
login = imap
login = pop3
mail_extra_groups = mail
auth = default
auth_mechanisms = plain
auth_userdb = passwd
auth_passdb = pam
auth_user = root

Have tried changeing auth_passdb to passwd
any help appreciated