[cc lang="bash"]
\$ vi /etc/postfix/master.cf
\$ /etc/init.d/postfix restart

\$ netstat -tulnp | grep master
tcp 0 0 0.0.0.0:465 0.0.0.0:* LISTEN 5398/master
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 5398/master

\$ openssl s_client -connect 10.20.30.40:465 -quiet
[/cc]

/etc/postfix/master.cf
[cc lang="bash"]
...
smtps inet n - - - - smtpd
-o smtpd_tls_wrappermode=yes
...
[/cc]