It works as follows: Hermes EMail Server has three basic elements. A POP3 server, that accepts connections from the email clients that want to read the user's mail; an SMTP server, that accepts that connections of any user that wants to send an email or other servers that want to deliver an email. It also has an SMTP agent that will take care of delivering the mails that are in the queue for users that aren't local.
Before starting to use this email server, it is necessary to configure it. This general configuration is essential for it to work. Nevertheless, all the rest of the settings are already configured by default.
Furthermore, the application's source code is included in the download for those people that want to check how it has been designed or to improve it.