In case you have a hosting account and you create an email address, you may consider the option to send and receive messages for granted, but in fact, that isn't always true. Sending e-mail messages isn't necessarily included in the hosting plans that providers offer and an SMTP service is necessary to be capable to do that. The abbreviation stands for Simple Mail Transfer Protocol and that is the software application that allows you to send out email messages. If you are using an e-mail app, it creates a connection to the SMTP server. The latter then requests the DNS data of the domain, which is a part of the receiving address to find out which mail server handles its e-mails. After some system information is exchanged, your SMTP server provides the message to the remote IMAP or POP server and the email is finally delivered in the corresponding mailbox. An SMTP server is required if you are using some kind of contact form as well, so in case you have a free of charge hosting package, for example, it is very likely that you will not be able to use such a form since many free of charge web hosting companies don't allow outgoing email messages.