What is Post Office Protocol?
{{IPstack}} In [[computing]], the '''Post Office Protocol version 3''' ('''POP3''') is an [[application layer| application-layer]] [[Internet standard]] [[protocol (computing)| protocol]] used by local [[e-mail]] clients to get [[e-mail]] from a remote mail [[server]] over a [[Internet protocol suite|TCP/IP]] connection. POP3 and [[IMAP4]] (Internet Message Access Protocol) are the two most widely accepted Internet standard protocols for e-mail retrieval. Almost all modern e-mail clients and servers support both. Many years ago, a proposal was outlined for a [http://www.pop4.org/pop4/pop4spec.html POP4 specification], complete with a working server implementation. The proposed POP4 extension adds basic folder management, multipart message support, as well as message flag management, allowing for a light protocol which supports some popular IMAP features which POP3 lacks. No progress has been found in the POP4 specification since [[2003]]. == Related Requests For Comments (RFCs) == * [[Rfc:1939|RFC 1939]] – Post Office Protocol - Version 3 (STD 53) * [[Rfc:1957|RFC 1957]] – Some Observations on Implementations of the Post Office Protocol (POP3) * [[Rfc:2195|RFC 2195]] – IMAP/POP AUTHorize Extension for Simple Challenge/Response * [[Rfc:2384|RFC 2384]] – POP URL Scheme * [[Rfc:2449|RFC 2449]] – POP3 Extension Mechanism * [[Rfc:2595|RFC 2595]] – Using TLS with IMAP, POP3 and ACAP * [[Rfc:3206|RFC 3206]] – The SYS and AUTH POP Response Codes * [[Rfc:5034|RFC 5034]] – The Post Office Protocol (POP3) Simple Authentication and Security Layer (SASL) Authentication Mechanism ==Related pages== * [[Internet Message Access Protocol]] (IMAP) * [[Simple Mail Transfer Protocol]] (SMTP) * [[E-mail client]] * [[Webmail]] * POP3 clients: [[getmail]], [[fetchmail]] * [[Email encryption]] [[Category:Computer protocols]] [[Category:E-mail]]