Sendmail
Sendmail is a widely used, open-source Mail Transfer Agent (MTA) that routes and delivers email messages between servers on the internet. It was originally developed in the 1980s and became a standard component of Unix-like operating systems, handling SMTP (Simple Mail Transfer Protocol) for sending, receiving, and forwarding emails. It is known for its flexibility and configurability, though it has a complex configuration syntax that can be challenging to manage.
Developers should learn or use Sendmail when working on legacy systems, Unix/Linux server administration, or email infrastructure projects that require a robust, customizable MTA. It is particularly useful in environments where fine-grained control over email routing, security policies, or integration with custom scripts is needed, such as in enterprise or academic settings. However, due to its complexity, it is often replaced by more modern alternatives for new projects.