The Sun Message Store and /var/mail support the Internet Mail Access Protocol version 4 (IMAP4) and the Post Office Protocol version 3 (POP3). Therefore, a mail client user can access either message store using either protocol. For example, a user's Inbox and other folders can be stored on the Sun Message Store and accessed using IMAP4 or POP3 or they can be stored in /var/mail and accessed using IMAP4 or POP3.