SMTP means Simple Mail Transfer Protocol.
It is the protocol used to communicate between mail servers on the internet. When b2evolution or PHP wants to send an email to a Recipient, it needs to contact a mail server (preferably directly the destination server, but it can be an intermediary) and send the email over. The protocol used for this dialog between b2evolution or PHP and the email server is SMTP.
Created by • Last edit by on Sep 06, 2016