SMTP, which is short for Simple Mail Transfer Protocol, is the software that enables you to send out emails from your email addresses. Without it, you won't be able to employ email apps or webmail. When you send a message, your SMTP server creates a connection to a DNS server to discover where the e-mails for the recipient domain are handled. Following that, it connects to the remote mail server and trades details. If the recipient mail box is present, your server sends the email to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox in which the receiver can access it. If you would like to be able to send emails, it is recommended to make sure that the web hosting company provides the service with their plans. Even if you make use of online form that site visitors use to contact you, you still require an active SMTP server for your hosting account for the form to operate.