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(messaging, protocol)
Version 3 of the Post Office Protocol. POP3 is defined in RFC 1081, written in November 1988 by Marshall Rose, which is based on RFC 918 (since revised as RFC 937). POP3 allows a client computer to retrieve electronic mail from a POP3 server via a (temporary) TCP/IP or otheronnection. It does not provide for sending mail, which is assumed to be done via SMTP or some other method.

POP is useful for computers, e.g. mobile or home computers, without a permanent network connection which therefore require a "post office" (the POP server) to hold their mail until they can retrieve it.

Although similar in form to the original POP proposed for the Internet community, POP3 is similar in spirit to the ideas investigated by the MZnet project at the University of California, Irvine, and is incompatible with earlier versions of POP.

Substantial work was done on examining POP in a PC-based environment. This work, which resulted in additional functionality in this protocol, was performed by the ACIS Networking Systems Group at Stanford University.

RFC 1082 (POP3 Extended Service) extends POP3 to deal with accessing mailboxes for mailing lists.


(Post Office Protocol 3) A programming interface (API) from the IETF that enables a user's email program to access the mail server (RFC 1939 standard). Email clients such as Outlook, Mail, Eudora and Thunderbird are typically configured to retrieve mail either via POP3 or IMAP4, the other popular standard.

POP3 is a simple system with limited selectivity. Incoming messages and attachments are downloaded when users check their mail, and POP is typically configured to delete the messages on the server after downloading. If the user opts to not delete them, the messages will download again the next time mail is checked. See IMAP4, email interfaces, SMTP and messaging system.

Incoming Mail Options
Most Internet mail services offer all three options. Users may choose IMAP if they need access from several computers or if they like to keep mail online indefinitely (see IMAP4).
References in periodicals archive ?
The XDove mail server named after the open source offering XMail and Dovecot enables them to quickly set up POP3 and IMAP mail server, create mail accounts after their own domain names, and maintain all-you-can-name mail server features over the Intranet and the Internet.
IGetMail is a Windows utility commonly installed on the Exchange Server to automatically download, sort and deliver POP3 email messages from multiple remote servers to a local Microsoft Exchange Server.
AGET the names of the POP3 and SMTP servers from your ISP.
the technology leader in unified threat management (UTM) solutions, today announced the release of a new POP3 proxy to its already robust zero-day protection engine, giving users of the Firebox X Core and Peak UTM appliances another tool in the fight against network threats.
Q I CANNOT use Outlook Express because an error message appears every time I try to open it which says: "The host POP3 could not be found.
OrcaFax[TM] is a secure, high-performance desktop fax service that allows subscribers to send and receive fax messages from Microsoft Outlook or any other POP3 email client.
Outlook Express asks for my incoming mail POP3 and outgoing mail SMTP.
SmoothZap includes transparent SMTP and POP3 proxies so that all email traffic, including any email received from employees' personal email accounts, is subject to anti-virus scanning.
SPARTAN Suite (System, Performance, Alerts, Reporting and Traffic Analysis for Networks) consists of a set of services that includes: monitoring of network services (SMTP, POP3, HTTP, NNTP, Ping, etc); bandwidth graphing; pro-active administration; and device resources and firewall monitoring, among others.