SMTP, which is short for Simple Mail Transfer Protocol, is the software that enables you to send out messages from your email addresses. Without this, you won't be able to use e-mail apps or webmail. When you send an email, your SMTP server connects to a DNS server to discover where the e-mails for the recipient domain are handled. After that, it connects to the remote email server and exchanges details. When the recipient mail box is available, your server transmits the message to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox where the recipient can see it. If you want to send e-mails, it is recommended to make certain that the hosting company has the service with their plans. Even though you work with an online form that website visitors use to make contact with you, you'll still need an active SMTP server for your hosting account for the web form to operate.