Mandrill is an email infrastructure service offered as an add-on for Mailchimp that you can use to send email notifications.
Login to Mailchimp then go to Automation and Transactional E-mail
Set Demo Usage - then Launch App - Yo uwill be redirected to Mandrill
Once you have set up a Mandrill account:
Create a Domain
...
Click the Settings tab from the left side navigation menu.
Click the Domains tab from the top navigation bar.
Click Set up your sending domain button. Add the domain from which you wish to send emails. Click the Add button.
You can view your current added domain in the Domain Details. Verify your Domain by clicking Verify a Domain button on the right side.
...