Simple Mail Transfer Protocol (SMTP) is a set of rules used while sending emails. Usually, this protocol is associated with IMAP or POP3. However, SMTP is utilized to deliver messages, while POP3 and IMAP are utilized to receive them. The SMTP testing tool identifies issues with email security in your server that can hinder your email delivery. It checks the health status of your outgoing email server and notifies you about the detected problems, such as connectivity issues, and how to tackle them. An SMTP test tool can identify SMTP server issues and troubleshoot them to keep your email secure and safe. The SSL Checker tool can verify that the SSL Certificate on your web server is properly installed and trusted. Header Analyzers can help you view and analyze message headers by displaying the information in a user-friendly manner and also by calling out various issues, such as suspected delivery delays that may require your attention.