Glossary definition of Post Office Protocol 3

Also known as: POP3

POP3 (Post Office Protocol 3) is a standard protocol used by a client to receive e-mail that has been sent to them over the Internet. The protocol is used to retrieve the client's e-mail from the server, and unless arrangements are made to save it, the copy on the server will be deleted after it has been downloaded.

POP3 is the most recent version of this protocol and is typically included in software e-mail applications, such as Outlook Express; it is also built into the popular browsers, e.g. Microsoft Explorer and Netscape. POP3 is usually employed together with SMTP (Simple Mail Transfer Protocol). IMAP (Internet Message Access Protocol) is an alternative protocol to POP3, with more features for handling the e-mail on the server.