SMTP, which is short for Simple Mail Transfer Protocol, is the software that allows you to send out e-mails from your email addresses. Without this, you will not be able to use email applications or webmail. Once you send a message, your SMTP server creates a connection to a DNS server to find out exactly where e-mails for the recipient domain name are handled. Following that, it creates a connection to the remote mail server and trades details. In case the recipient mailbox is accessible, your server transmits the e-mail to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox in which the recipient can see it. If you wish to send emails, you should always make certain that the hosting company provides the service with their plans. Even when you make use of online form that website visitors use to get hold of you, you still require an active SMTP server for your hosting account for the form to function.