If you'd like to send out e-mail messages through an e-mail address with your very own domain, you have to make sure that the company will provide you with usage of their SMTP server. The latter is the software that enables email messages to be sent. SMTP is an acronym for Simple Mail Transfer Protocol and it manages all outgoing e-mails from applications, webmail and contact web forms. Whenever a message is sent out, the SMTP server confirms with all of the DNS servers globally where the e-mails for the receiving domain are handled and as soon as it acquires this info, it will connect to the remote POP/IMAP server to find out if the recipient mail box is out there. If it does, the SMTP server directs the message body and then the receiving server sends it to the mail box in which the recipient can open it and read it. Without an SMTP server on your server, you won't be capable to mail out emails at all.