SMTP, which stands for Simple Mail Transfer Protocol, is the software that enables you to send messages from your email addresses. Without it, you won't be able to employ e-mail apps or webmail. When you send a message, your SMTP server creates a connection to a DNS server to discover exactly where emails for the recipient domain name are handled. Subsequently, it connects to the remote mail server and trades information. In case the recipient mailbox exists, your server sends the e-mail to the receiving POP/IMAP server and the latter brings that email to the precise mailbox where the recipient can see it. If you would like to be able to send emails, it is best to make sure that the web hosting company provides the service with their packages. Even if you work with an online form that visitors use to get hold of you, you'll still require an active SMTP server for your hosting account for the form to function.