SMTP, which is short for Simple Mail Transfer Protocol, is the software that permits you to send e-mails from your email addresses. Without it, you will not be able to use e-mail apps or webmail. Whenever you send an e-mail, your SMTP server connects to a DNS server to discover exactly where e-mails for the recipient domain are taken care of. Subsequently, it creates a connection to the remote email server and trades details. When the recipient mailbox is accessible, your server transmits the message to the receiving POP/IMAP server and the latter delivers that e-mail to the specific mailbox where the recipient can get it. If you'd like to send e-mails, it is best to make certain that the website hosting company provides the service with their plans. Even when you use an online form that website visitors use to make contact with you, you still need an active SMTP server for your hosting account for the form to operate.