Overview:
A departmental mail server usually acts as a mailbox server that holds mail for its clients until they are ready to download it for their readers. The mailbox service supports mobile users and systems that do not receive mail in real time. Two commonly used techniques that Linux offers for creating a mailbox server are Post Office Protocol (POP) and Internet Message Access Protocol (IMAP). This chapter uses both protocols to configure a Linux system to act as a department mailbox server.
In addition to the essential mailbox services, Linux systems offer some additional mail services that you may want to use. These include spam filters and tools that are designed to help you limit the amount of unwanted junk mail that bombards your users.