Setup a POP3 Server that enables SSL/TLS function

OS: CentOS4.5
POP3 Server: dovecot

Setup procedure:
1. Edit /etc/dovecot.conf
->
protocols = pop3 pop3s
imap_listen = [::]
pop3_listen = [::]
ssl_disable = no
ssl_cert_file = /usr/share/ssl/certs/dovecot.pem
ssl_key_file = /usr/share/ssl/private/dovecot.pem
disable_plaintext_auth = no
login_dir = /var/run/dovecot-login
login = imap
login = pop3
mbox_locks = fcntl
auth = default
auth_mechanisms = plain
auth_userdb = passwd
auth_passdb = pam
auth_user = root

2. Start dovecot
# service dovecot start; chkconfig dovecot on