Mail servers make it possible to set up e-mail messaging systems on private intranets or on the Internet itself. These servers use a variety of standards-based mail protocols including SMTP, POP3, and IMAP4 to help you set up mail accounts, manage the system, route messages, etc. While some mail servers also allow you to create, manage, and serve mailing lists, in most cases a separate List Server, is needed to handle these tasks. Some mail servers help corporations and ISPs process several million messages a day, while others are designed for meeting the needs of smaller organizations and internal intranets.