Fetchmail

Fetchmail is a free and open-source computer utility that retrieves mail from remote mail servers, such as those running POP3, POP3S, IMAP, IMAPS, or APOP, and forwards it to a local mail delivery agent. It is commonly used on Unix-like operating systems to collect email from various accounts and deliver it to a single local mailbox.

The primary function of fetchmail is to act as a mail retriever. It connects to specified remote mail servers, downloads new messages, and then typically passes them to a local mail transfer agent (MTA) or directly to a local mailbox file. This allows users to manage all their email from a single, consolidated location.

Fetchmail supports a wide range of authentication methods and protocols, making it versatile for different server configurations. It can be configured to run periodically, often via cron jobs, to ensure that new mail is regularly fetched. This automation simplifies the process of email collection for users who do not wish to connect to each mail server individually.

The configuration for fetchmail is typically done through a `.fetchmailrc` file in the user's home directory. This file specifies the mail servers to connect to, the protocols to use, authentication credentials, and the destination for the retrieved mail. Fetchmail can also be used to delete messages from the server after retrieval, or to leave them on the server, depending on the user's preference and configuration. Its flexibility and robustness have made it a popular choice for system administrators and users managing multiple email accounts.