SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that allows you to send messages from your email addresses. Without it, you will not be able to use e-mail applications or webmail. Once you send an e-mail, your SMTP server connects to a DNS server to determine exactly where e-mails for the recipient domain name are managed. Following that, it creates a connection to the remote email server and trades information. If the recipient mail box is available, your server transmits the e-mail to the receiving POP/IMAP server and the latter delivers that message to the precise mailbox where the receiver can get it. If you wish to send e-mails, it is recommended to make sure that the web hosting company offers the service with their packages. Even if you work with an online form that visitors use to contact you, you will still need an active SMTP server for your hosting account for the web form to work.