A mail server is a computer system that sends, receives, and stores email messages. It uses specific protocols, such as SMTP (Simple Mail Transfer Protocol) for sending emails and IMAP (Internet Message Access Protocol) or POP3 (Post Office Protocol) for retrieving them. Mail servers ensure that emails are delivered to the correct recipients and can manage large volumes of messages efficiently. Mail servers can be part of a larger network, often working alongside other servers to provide services like web hosting or file storage. They can be hosted on-premises or in the cloud, allowing users to access their emails from various devices, such as computers and smartphones.