When you have a website hosting plan and you set up an email address, you may take the option to send out and receive messages for granted, but in fact, that isn't always true. Sending emails is not necessarily included in the hosting plans that service providers feature and an SMTP service is necessary to be able to do that. The acronym means Simple Mail Transfer Protocol and this is the set of scripts that enables you to send out e-mails. If you are using an e-mail application, it creates a connection to the SMTP server. The latter then requests the DNS records of the domain, which is a part of the receiving address to find out which email server deals with its emails. After some 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 sort of contact page form also, so in case you have a free hosting package, as an example, it is very likely that you won't have the ability to make use of this type of form since many free of charge hosting providers do not allow outgoing e-mail messages.