When you've got a hosting plan and you set up an email address, you might consider the option to send out and receive messages for granted, but in fact, this is not always the case. Sending emails is not always part of the hosting plans that companies offer and an SMTP service is needed to be capable to do that. The acronym means Simple Mail Transfer Protocol and that is the set of scripts that allows you to send emails. If you are using an email application, it connects to the SMTP server. The latter then queries the DNS data of the domain name, which is a part of the receiving address to find out which email server deals with its emails. After some system data is interchanged, your SMTP server delivers the message to the remote IMAP or POP server and then the e-mail is finally delivered in the corresponding mailbox. An SMTP server is required if you use some sort of contact page form too, so if you work with a free of charge hosting plan, for instance, it is likely that you will not be able to make use of such a form as many cost-free web hosting companies do not allow outgoing email messages.