SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that permits you to send out emails from your email addresses. Without this, you won't be able to employ email apps or webmail. After you send an e-mail, your SMTP server connects to a DNS server to learn exactly where emails for the recipient domain are taken care of. Subsequently, it connects to the remote email server and trades information. In case the recipient mailbox is present, your server sends the email to the receiving POP/IMAP server and the latter delivers that message to the particular mailbox in which the receiver can get it. If you'd like to be able to send e-mails, you should always ensure that the hosting company offers the service with their packages. Even if you use an online form that visitors use to make contact with you, you still need an active SMTP server for your hosting account for the form to function.