RFC 937 (rfc937) - Page 1 of 24
Post Office Protocol: Version 2
Alternative Format: Original Text Document
Network Working Group M. Butler
Request for Comments: 937 J. Postel
D. Chase
J. Goldberger
J. K. Reynolds
Obsoletes: RFC 918 ISI
February 1985
POST OFFICE PROTOCOL - VERSION 2
Status of this Memo
This RFC suggests a simple method for workstations to dynamically
access mail from a mailbox server. This RFC specifies a proposed
protocol for the ARPA-Internet community, and requests discussion and
suggestions for improvement. This memo is a revision of RFC 918.
Distribution of this memo is unlimited.
Introduction
The intent of the Post Office Protocol Version 2 (POP2) is to allow a
user's workstation to access mail from a mailbox server. It is
expected that mail will be posted from the workstation to the mailbox
server via the Simple Mail Transfer Protocol (SMTP). For further
information see RFC-821 [1] and RFC-822 [2].
This protocol assumes a reliable data stream such as provided by TCP
or any similar protocol. When TCP is used, the POP2 server listens
on port 109 [4].
System Model and Philosophy
While we view the workstation as an Internet host in the sense that
it implements IP, we do not expect the workstation to contain the
user's mailbox. We expect the mailbox to be on a server machine.
We believe it is important for the mailbox to be on an "always up"
machine and that a workstation may be frequently powered down, or
otherwise unavailable as an SMTP server.
POP2 is designed for an environment of workstations and servers on a
low-delay, high-throughput, local networks (such as Ethernets). POP2
may be useful in other environments as well, but if the environment
is substantially different, a different division of labor between the
client and server may be appropriate, and a different protocol
required.
Suppose the user's real name is John Smith, the user's machine is
called FIDO, and that the mailbox server is called DOG-HOUSE. Then
Butler, et. al.