Post Office Protocol - Version 3
RFC 1939
Document | Type |
RFC - Internet Standard
(May 1996; Errata)
Obsoletes RFC 1725
Also known as STD 53
Was draft-myers-pop-pop3 (individual)
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Authors | Marshall Rose , John Myers | ||
Last updated | 2020-01-21 | ||
Stream | Legacy stream | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 1939 (Internet Standard) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group J. Myers Request for Comments: 1939 Carnegie Mellon STD: 53 M. Rose Obsoletes: 1725 Dover Beach Consulting, Inc. Category: Standards Track May 1996 Post Office Protocol - Version 3 Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Table of Contents 1. Introduction ................................................ 2 2. A Short Digression .......................................... 2 3. Basic Operation ............................................. 3 4. The AUTHORIZATION State ..................................... 4 QUIT Command ................................................ 5 5. The TRANSACTION State ....................................... 5 STAT Command ................................................ 6 LIST Command ................................................ 6 RETR Command ................................................ 8 DELE Command ................................................ 8 NOOP Command ................................................ 9 RSET Command ................................................ 9 6. The UPDATE State ............................................ 10 QUIT Command ................................................ 10 7. Optional POP3 Commands ...................................... 11 TOP Command ................................................. 11 UIDL Command ................................................ 12 USER Command ................................................ 13 PASS Command ................................................ 14 APOP Command ................................................ 15 8. Scaling and Operational Considerations ...................... 16 9. POP3 Command Summary ........................................ 18 10. Example POP3 Session ....................................... 19 11. Message Format ............................................. 19 12. References ................................................. 20 13. Security Considerations .................................... 20 14. Acknowledgements ........................................... 20 15. Authors' Addresses ......................................... 21 Appendix A. Differences from RFC 1725 .......................... 22 Myers & Rose Standards Track [Page 1] RFC 1939 POP3 May 1996 Appendix B. Command Index ...................................... 23 1. Introduction On certain types of smaller nodes in the Internet it is often impractical to maintain a message transport system (MTS). For example, a workstation may not have sufficient resources (cycles, disk space) in order to permit a SMTP server [RFC821] and associated local mail delivery system to be kept resident and continuously running. Similarly, it may be expensive (or impossible) to keep a personal computer interconnected to an IP-style network for long amounts of time (the node is lacking the resource known as "connectivity"). Despite this, it is often very useful to be able to manage mail on these smaller nodes, and they often support a user agent (UA) to aid the tasks of mail handling. To solve this problem, a node which can support an MTS entity offers a maildrop service to these less endowed nodes. 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. Usually, this means that the POP3 protocol is used to allow a workstation to retrieve mail that the server is holding for it. POP3 is not intended to provide extensive manipulation operations of mail on the server; normally, mail is downloaded and then deleted. A more advanced (and complex) protocol, IMAP4, is discussed in [RFC1730]. For the remainder of this memo, the term "client host" refers to a host making use of the POP3 service, while the term "server host" refers to a host which offers the POP3 service. 2. A Short Digression This memo does not specify how a client host enters mail into the transport system, although a method consistent with the philosophy of this memo is presented here: When the user agent on a client host wishes to enter a messageShow full document text