When you've got a hosting plan and you create an email address, you might consider the option to send and receive emails for granted, but in fact, this is not always the case. Sending emails is not necessarily a part of the web hosting plans that companies have and an SMTP service is required to be able to do that. The acronym means Simple Mail Transfer Protocol and this is the piece of software that enables you to send out email messages. If you are using an e-mail application, it creates a connection to the SMTP server. The latter then looks up the DNS records of the domain, which is a part of the receiving address to find out which mail server handles its email messages. After system information is interchanged, your SMTP server delivers the message to the remote IMAP or POP server and the e-mail is finally delivered in the matching mailbox. An SMTP server is required if you are using some sort of contact page as well, so if you have a no charge hosting plan, for instance, it is likely that you won't be able to make use of such a form as most free website hosting companies don't allow outgoing e-mail messages.