SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that permits you to send e-mail messages from your email addresses. Without this, you won't be able to employ email applications or webmail. Once 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 details. If the recipient mail box is accessible, your server sends the e-mail to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox where the recipient can get it. If you would like to be able to send e-mails, it is best to make certain that the website hosting company has the service with their packages. Even if you work with an online form that website visitors use to contact you, you still require an active SMTP server for your hosting account for the web form to work.