SMTP, which is short for Simple Mail Transfer Protocol, is the software that enables you to send e-mail messages from your email addresses. Without it, you won't be able to employ e-mail applications or webmail. After you send an e-mail, your SMTP server creates a connection to a DNS server to determine where the emails for the recipient domain name are handled. Following that, it creates a connection to the remote mail server and exchanges information. In case the recipient mail box exists, your server sends the email to the receiving POP/IMAP server and the latter delivers that email to the precise mailbox in which the receiver can see it. If you'd like to be able to send e-mails, it is best to make certain that the hosting company has the service with their plans. Even though you make use of online form that site visitors use to contact you, you still need an active SMTP server for your hosting account for the form to work.