Set Up Wordpress To Use Mandrill To Send Emails

There is a simple plugin wpMandrill which pretty much automates the whole process.
1) Backup your site
2) Plugins > Add New > Search for "wpMandrill"
3) Download, Install & Enable
4) Within Mandrill generate new API Settings > AMTP & API Info > New API Key
5) Paste into Wordpress Mandrill Plugin
6) Add reply to address
7) Test
8) Add/Edit any SPF records
9) Edit /etc/postfix/main.cf to prevent the domain sending unauthorized emails.
e.g. authorized_submit_users = !{username}, static:anyone

Does not prevent someone not using postfix if just coding smtp connect
grep "smtp.*to=.*" /var/log/syslog | grep -v 250