When you have a cloud hosting plan and you create an e-mail address, you may take the option to send and receive messages for granted, but in fact, this is not always true. Sending e-mails is not always part of the hosting packages that companies have and an SMTP service is required to be able to do that. The acronym signifies Simple Mail Transfer Protocol and this is the set of scripts that enables you to send out emails. If you use an e-mail app, it connects to the SMTP server. The latter then looks up the DNS records of the domain name, which is a part of the receiving address to find out which mail server handles its e-mails. After system data is exchanged, your SMTP server provides the email to the remote IMAP or POP server and the e-mail is finally delivered in the corresponding mailbox. An SMTP server is needed if you are using some kind of contact page as well, so if you work with a free hosting plan, for example, it's probable that you will not be able to make use of such a form as most free of charge website hosting service providers do not allow outgoing emails.