Postfix is a popular open-source mail transfer agent (MTA) used to route and deliver email on Unix-like operating systems. It is designed to be fast, secure, and easy to configure, making it a preferred choice for many system administrators. Postfix handles the sending and receiving of emails, managing tasks such as queuing messages and ensuring they reach their intended recipients. One of the key features of Postfix is its modular architecture, which allows for easy integration with various plugins and services. This flexibility enables users to customize their email systems according to specific needs, such as implementing spam filtering or supporting different authentication methods. Overall, Postfix is a reliable solution for managing email communications.