RFC 1939 Internet Standard Submission and access

Post Office Protocol - Version 3

The Post Office Protocol - Version 3 (POP3) is intended to permit a workstation to dynamically access a maildrop on a server host in a useful fashion. [STANDARDS-TRACK]

Status
Internet Standard. The top of the standards track. An old document can hold this label while the document that replaced it holds a lower one, which is the single most misleading thing about RFC status.
Published
May 1996
Authors
J. Myers, M. Rose
Read it
rfc-editor.org · errata · DOI

Replaces RFC 1081: Post Office Protocol: Version 3, RFC 1225: Post Office Protocol: Version 3, RFC 1460: Post Office Protocol - Version 3, RFC 1725: Post Office Protocol - Version 3.

This document is current and has been amended. 4 later RFCs have changed part of it. Nothing on the RFC itself tells you this.

Normative requirements

Every sentence in this RFC carrying an RFC 2119 keyword, with the section it came from. 6 must, 0 should, 1 may.

3 Basic Operation

  • MUSTServers MUST send the "+OK" and "-ERR" in upper case.
  • MUSTA server MUST respond to an unrecognized, unimplemented, or syntactically invalid command by responding with a negative status indicator.
  • MUSTA server MUST respond to a command issued when the session is in an incorrect state by responding with a negative status indicator.
  • MAYA POP3 server MAY have an inactivity autologout timer.
  • MUSTSuch a timer MUST be of at least 10 minutes' duration.

6 The UPDATE State

  • MUSTIf a session terminates for some reason other than a client-issued QUIT command, the POP3 session does NOT enter the UPDATE state and MUST not remove any messages from the maildrop.

7 Optional POP3 Commands

  • MUSTThe syntax of the timestamp corresponds to the `msg-id' in [RFC822], and MUST be different each time the POP3 server issues a banner greeting.

Every current email RFC