SMTP, which is short for Simple Mail Transfer Protocol, is the software that permits you to send e-mails from your email addresses. Without it, you will not be able to employ e-mail applications or webmail. When you send an e-mail, your SMTP server creates a connection to a DNS server to find out where the emails for the recipient domain are handled. Then, it connects to the remote mail server and exchanges information. When the recipient mail box exists, your server sends the e-mail to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox in which the receiver can find it. If you would like to send e-mails, it is best to make certain that the hosting company has the service with their plans. Even though you use an online form that visitors use to make contact with you, you still require an active SMTP server for your hosting account for the form to operate.