POP3, Post Office Protocol 3

POP3 is used by millions of users and web servers. It enables the easy management of reading, sending and saving email as well downloading attachments. POP3 is a standard protocol built into many email clients, including Microsoft Outlook Express and Eudora. It is also built into Navigator and Internet Explorer browsers. POP3 is designed to automatically delete messages from a server as soon as it has been downloaded to the hard drive. Some mail clients allow administrators and users to store messages for a specific amount of time. IMAP (Internet Message Access Protocol) is an alternative to POP3. It gives a user more capability for keeping and managing messages on a server. Both of these protocols differ from SMTP (Simple Mail Transfer Protocol), a method primarily used to only send email. A user sends mail via SMTP and a mail handler receives it on their behalf. The message is then read using POP or IMAP.