If you need to send email messages through an email address with your domain, you have to make sure that the company will give you access to their SMTP server. The aforementioned is the software which enables emails to be sent. SMTP is an abbreviation for Simple Mail Transfer Protocol and it deals with all outgoing email messages from applications, webmail and contact forms. Whenever a message is sent out, the SMTP server confirms with all the DNS servers globally where the e-mails for the receiving domain are handled and once it obtains this info, it will connect into the remote POP/IMAP server to see if the recipient mail box exists. If it does, the SMTP server transmits the e-mail body and so the receiving server delivers it to the mail box where the recipient can open it and read it. Without having a SMTP server on your server, you will not be allowed to send emails at all.