SMTP, which stands for Simple Mail Transfer Protocol, is the software that allows you to send messages from your email addresses. Without this, you won't be able to employ e-mail applications or webmail. Once you send an e-mail, your SMTP server creates a connection to a DNS server to discover exactly where emails for the recipient domain name are taken care of. Following that, it creates a connection to the remote mail server and trades information. If the recipient mail box is available, your server sends the e-mail to the receiving POP/IMAP server and the latter brings that email to the particular mailbox in which the receiver can see it. If you want to be able to send e-mails, you should always make certain that the hosting company has the service with their packages. Even though you make use of online form that website visitors use to contact you, you'll still need an active SMTP server for your hosting account for the form to work.