SMTP, which stands for Simple Mail Transfer Protocol, is the software that permits you to send out messages from your email addresses. Without this, you will not be able to use e-mail applications or webmail. When you send an email, your SMTP server creates a connection to a DNS server to determine where the emails for the recipient domain name are handled. Subsequently, it creates a connection to the remote mail server and exchanges details. If the recipient mailbox is accessible, your server transmits the message to the receiving POP/IMAP server and the latter brings that message to the specific mailbox where the recipient can get it. If you wish to be able to send e-mails, it is recommended to make sure that the website hosting company has the service with their plans. Even though you make use of online form that visitors use to make contact with you, you still require an active SMTP server for your hosting account for the web form to work.