If you wish to send out emails using an e-mail address with your own domain, you have to make sure that the provider will give you usage of their SMTP server. The aforementioned is the software which allows e-mail messages to be sent out. SMTP is an abbreviation for Simple Mail Transfer Protocol and it addresses all outbound e-mails from programs, webmail and contact web forms. Whenever a message is sent, the SMTP server checks with all the DNS servers around the world where the emails for the receiving domain name are handled and once it obtains this info, it will connect into the remote POP/IMAP server to find out if the recipient mailbox exists. If it does, the SMTP server transmits the e-mail body while the receiving server sends it to the mailbox where the recipient can open it up and read it. Without having a SMTP server on your end, you will not be able to send out emails at all.