SMTP, which is short for Simple Mail Transfer Protocol, is the software that allows you to send out e-mail messages from your email addresses. Without this, you will not be able to employ e-mail apps or webmail. Whenever you send an e-mail, your SMTP server creates a connection to a DNS server to find out exactly where emails for the recipient domain are taken care of. Subsequently, it connects to the remote email server and trades details. If the recipient mail box is present, your server transmits the e-mail to the receiving POP/IMAP server and the latter brings that email to the particular mailbox where the recipient can access it. If you want to be able to send e-mails, it is recommended to make sure that the web hosting company provides the service with their packages. Even though you use an online form that website visitors use to get hold of you, you still require an active SMTP server for your hosting account for the form to operate.