SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that permits you to send messages from your email addresses. Without it, you will not be able to use email apps or webmail. Once you send an email, your SMTP server connects to a DNS server to find out exactly where e-mails for the recipient domain are handled. Then, it connects to the remote email server and trades information. When the recipient mail box is present, your server transmits the message to the receiving POP/IMAP server and the latter brings that email to the precise mailbox in which the receiver can find it. If you'd like to send e-mails, you should always make certain that the web hosting company offers the service with their packages. Even if 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 web form to operate.