PHP Mailer & SMTP Mail
Implementation of SMTP Mail script and php mail. PHPmail will be the default Mailer after the installation. Over the ACP the Siteadmin can change the configuration and test it. If the test complete without any error, the config will be set and any mail will send over the smtp server.
What happens if the SMTP Server doesn't response to a request? The Server will retry the process few times. After the limitation the server will send the mail over the intern PHPMail function.