Sendmail is one of the oldest and most widely used mail transfer agents (MTAs) on Unix-like systems for sending emails. It is known for its powerful and flexible features but can be complex to configure. Sendmail acts as a background process that sends, receives, and routes email messages, handling tasks from accepting emails from a user's mail client to delivering them to the recipient's mail server. Despite its complexity, it's highly regarded for its robustness and is a standard MTA in many web hosting environments.
