SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that allows you to send e-mail messages from your email addresses. Without this, you won't be able to employ email apps or webmail. Every time you send an e-mail, your SMTP server creates a connection to a DNS server to find out where the e-mails for the recipient domain are taken care of. After that, it creates a connection to the remote email server and trades information. When the recipient mail box is available, your server sends the email to the receiving POP/IMAP server and the latter delivers that email to the specific mailbox where the recipient can see it. If you'd like to be able to send e-mails, it is recommended to make certain that the hosting company offers the service with their plans. Even when you work with an online form that visitors use to contact you, you will still need an active SMTP server for your hosting account for the web form to operate.