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