SMTP, which stands for Simple Mail Transfer Protocol, is the software that permits you to send out emails from your email addresses. Without this, you will not be able to use email applications or webmail. When you send an email, your SMTP server creates a connection to a DNS server to find out exactly where e-mails for the recipient domain are managed. Subsequently, it creates a connection to the remote mail server and trades information. When the recipient mailbox is present, your server sends the email to the receiving POP/IMAP server and the latter brings that message to the particular mailbox where the receiver can find it. If you would like to be able to send e-mails, you should always make certain that the web hosting company provides the service with their plans. Even though you use an online form that website visitors use to make contact with you, you will still require an active SMTP server for your hosting account for the form to work.