Interactive Mail Access Protocol: Version 2 (RFC1176)
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2019-Feb-11
Internet Society Requests For Comment (RFCs)
This RFC suggests a method for personal computers and workstations to dynamically access mail from a mailbox server ("repository"). It obosoletes RFC 1064. This RFC specifies an Experimental Protocol for the Internet community. Discussion and suggestions for improvement are requested. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol.
Network Working Group M. Crispin Request for Comments: 1176 Washington Obsoletes: RFC 1064 August 1990
INTERACTIVE MAIL ACCESS PROTOCOL - VERSION 2
Status of this Memo
This RFC suggests a method for personal computers and workstations to dynamically access mail from a mailbox server ("repository"). It obosoletes RFC 1064. This RFC specifies an Experimental Protocol for the Internet community. Discussion and suggestions for improvement are requested. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.
The intent of the Interactive Mail Access Protocol, Version 2 (IMAP2) is to allow a workstation, personal computer, or similar small machine to access electronic mail from a mailbox server. Since the distinction between personal computers and workstations is blurring over time, it is desirable to have a single solution that addresses the need in a general fashion. IMAP2 is the "glue" of a distributed electronic mail system consisting of a family of client and server implementations on a wide variety of platforms, from small single- tasking personal computing engines to complex multi-user timesharing systems.
Although different in many ways from the Post Office Protocols (POP2 and POP3, hereafter referred to collectively as "POP") described in RFC 937 and RFC 1081, IMAP2 may be thought of as a functional superset of these. RFC 937 was used as a model for this RFC. There was a cognizant reason for this; POP deals with a similar problem, albeit with a less comprehensive solution, and it was desirable to offer a basis for comparison.
Like POP, IMAP2 specifies a means of accessing stored mail and not of posting mail; this function is handled by a mail transfer protocol such as SMTP (RFC 821).
This protocol assumes a reliable data stream such as provided by TCP or any similar protocol. When TCP is used, the IMAP2 server listens on port 143.
Crispin [Page 1]
RFC 1176 IMAP2 August 1990
System Model and Philosophy
Electronic mail is a primary means of communication for the widely spread Internet community. The advent of distributed personal computers and workstations has forced a significant rethinking of the mechanisms employed to manage electronic mail. With mainframes, each user tends to receive and process mail at the computer he uses most of the time, his "primary host". The first inclination of many users when an independent workstation is placed in front of them is to begin receiving mail at the workstation, and many vendors have implemented facilities to do this. However, this approach has several disadvantages:
(1) Personal computers and many workstations have a software design that gives full control of all aspects of the system to the user at the console. As a result, background tasks such as receiving mail may not run for long periods of time; either because the user is asking to use all the machine’s resourc...