In case you have a web hosting package and you set up an e-mail address, you may take the option to send out and receive emails for granted, however, this isn't always the case. Sending e-mails isn't always part of the web hosting packages that companies offer and an SMTP service is necessary to be capable to do that. The abbreviation represents Simple Mail Transfer Protocol and this is the set of scripts that enables you to send out emails. If you use an email application, it connects to the SMTP server. The latter then queries the DNS data of the domain, which is a part of the receiving address to find out what mail server deals with its emails. After some system information is exchanged, your SMTP server delivers the email to the remote IMAP or POP server and then the e-mail is finally delivered in the matching mailbox. An SMTP server is needed if you use some sort of contact page form also, so in case you have a no charge hosting package, for instance, it is likely that you will not be able to use such a form as many free hosting companies don't allow outgoing emails.