Easiest way to setup a SMTP server to receive mail?

Postfix, Exim, Sendmail and the rest are Mail Transfer Agents and can act as a Mail Submission Agent, Mail Exchange, Mail Transfer Agent, and Mail Delivery Agent. Given the proper cofiguration they will both send and receive email. (If you want to run your own Mail Exchange (MX) server you need a fixed address, and should get your IP address provider to configure your PTR address with your mail servers domain name.)

However, to retrieve email from a service like mailinator you need a program like fetchmail which will read mail from an inbox and pass it to your local MSA (Mail Submission Agent). The trick with a service like mailinator could be to configure pick up addresses dynamically.

You should definitely try iRedMail

• Deploy full-featured mail server in LESS THAN 1 MINUTE, low maintenance after deployed.
• Unlimited number of virtual mail domains, users, mail lists, aliases, admins.

Just download, extract and run the script.

Installation guide