SMTP stands for Simple Mail Transfer Protocol. It’s the standard protocol for sending emails over the Internet. In order to send and receive messages, you need an email client or web-based mail service that uses the SMTP for the sending of emails and POP3 or IMAP (preferably both) for email receiving. Most email providers deploy all necessary standards, but you should check if they’ll give you access to all protocols and features, see if they provide secure email connections. If you’re looking for free email hosting for your site and you want to send emails to your users make sure that your hosting provider offers free SMTP access.
How Does It Work?
The Simple Mail Transfer Protocol uses the Internet port 25 or sometimes port 587. To protect the emails you send you can use SSL encrypted SMTP mail connections known as SMTPS.
It must be noted that SMTP only delivers email. This is done when the email client sends the message to the SMTP server where the message is kept and the recipient needs to use POP3 or IMAP to retrieve it. The SMTP transmits the outgoing emails between several severs if it’s necessary. If the client cannot succeed in sending the message it notifies the user.