SMTP, which is short for Simple Mail Transfer Protocol, is the software that permits you to send e-mails from your email addresses. Without this, you will not be able to employ e-mail apps or webmail. After you send a message, your SMTP server connects to a DNS server to discover where the emails for the recipient domain are managed. After that, it creates a connection to the remote email server and exchanges details. When the recipient mail box exists, your server transmits the e-mail to the receiving POP/IMAP server and the latter brings that e-mail to the particular mailbox where the recipient can find it. If you would like to send e-mails, you should always make certain that the hosting company has the service with their packages. Even if you work with an online form that site visitors use to contact you, you'll still need an active SMTP server for your hosting account for the web form to operate.