RFC relevance of possible

As per Relevance of the word possible, we have this rfc below:

Network Working Group J. K.
Request for Comments: 918
October 1984

POST OFFICE

Status of this

This RFC suggests a simple method for workstations to
access mail from a mailbox server. This RFC specifies a
protocol for the ARPA-Internet community, and requests discussion
suggestions for improvement

The intent of the Post Office Protocol (POP) is to allow a user'
workstation to access mail from a mailbox server. It is
that mail will be posted from the workstation to the mailbox
via the Simple Mail Transfer Protocol (SMTP). For
information see RFC-821 [1] and RFC-822 [2].

The status of this protocol is experimental, and this protocol
dependent upon TCP

The

The protocol is for the server to be listening for a connection
When a connection is opened the server sends a greeting message
waits for commands. When commands are received the server acts
them and responds with replies

The client opens a connection, waits for the greeting, then sends
USER and then the PASS commands to establish authorization to
mailboxes. The client begins a mail reading transaction with
an RDEL (to read and delete all messages from a mailbox) or a
(to simply read all messages from a mailbox). The server opens
locks the mailbox, and responds with the number of characters in
mailbox. Then the client asks for the data to be sent by issuing
RCEV command. The server responds by sending the mail data.
all the data has been received the client sends the RCVD command.
the transaction started with the RDEL command the server now
the mail data from the mailbox. In any case, the server closes
unlocks the mailbox. The client terminates the session with the
command

Reynolds [Page 1]

Post Office Protocol RFC 918

The Normal

Client
------ ------
Wait for
Open Connection -->
<-- +
Wait for
USER Fred -->
<-- +
Wait for
PASS password -->
<-- +
Wait for
RDEL mailbox --> (open and lock mailbox
<-- #
Wait for
RCEV -->
<-- (send a copy of mail
Wait for
RCVD --> (deletes mail from mailbox,
and close mailbox
<-- +
Wait for
QUIT -->
<-- +
Close connection --> <-- Close
Wait for Connection (go back to start

Definitions of Commands and

Summary of Commands and

Commands
-------- -------
USER name +
PASS password -
RETR mailbox #
RDEL

Reynolds [Page 2]

Post Office Protocol RFC 918

USER

This command identifies the user to the server. It must
followed by the PASS command

Possible responses: "+OK" or "-ERR

PASS

The PASS command carries the password authenticating this user
Together the USER name and PASS password are used by the
to control access to the mailboxes

Possible responses: "+OK" or "-ERR

RETR

This command begins a mail reading transaction. The
command is used to read all the messages in a mailbox
deleting them. It must be followed by the RCEV command

Possible responses: "#xxx" or "-ERR

RDEL

This command begins a mail reading transaction. The
command is used to read all the messages in a mailbox
delete them. It must be followed by the RCEV command

Possible responses: "#xxx" or "-ERR

This command confirms that the client is ready to receive
mail data. It must be followed by the RCVD command

Possible responses: "+OK" or (connection aborted

This command confirms that the client has received and
the mail. The RCVD command ends the mail reading transaction
In the case of the RDEL transaction, it is possible that
mail is not necessarily deleted. This is indicated by an
reply

Possible responses: "+OK" or "-ERR

Reynolds [Page 3]

Post Office Protocol RFC 918

This command indicates the client is done with the session
The server sends an OK response and then closes the connection

Possible responses: "+OK" then

This is the no operation command. It causes no action on
part of the server except an OK response

Possible response: "+OK

This command causes the server to abort the current
and return to waiting for a command (one of RDEL, RETR, QUIT
NOOP, or RSET). When aborting a transaction the server
take care to properly close and unlock the mailbox

Possible response: "+OK

I would like to acknowledge the contributions of Jon Postel,
Goldberger, Dale Chase, and Michael Butler in the development of
Post Office Protocol

[1] Postel, J., "Simple Mail Transfer Protocol", RFC-821,
USC/Information Sciences Institute, August 1982.

[2] Crocker, D., "Standard for the Format of ARPA-Internet
Messages", RFC-822, University of Delaware, August 1982.

Reynolds [Page 4]

Post Office Protocol RFC 918

+---+ +---+ +---+ +---+ +---+
Open | | +OK | | | | +OK | | | | +OK
----->| S |--+-->| C |------>| S |------>| C |------>| S |---->+
| | ^ | | USER | | | | PASS | | |
+---+ | +---+ +---+ +---+ +---+ |
| | -ERR | -ERR |
| V V |
+<-----------+<----------------+<----------------------+ |
| |
V +---+ +---+ |
+----->| | QUIT | | +OK |
| C |------>| S |----->Close |
+----->| | | | |
^ +---+ +---+ |
|
+<-------------------------------------------------------------+
| ^
| +---+ +---+ +---+ +---+ +---+ +---+ |
| | |RETR | | #xxx | |RECV | |DATA | |RCVD | |+OK |
+->| C |---->| S |----->| C |---->| S |---->| C |---->| S |--->+
| | | or | | | | | | | | | | ^
| +---+ RDEL+---+ +---+ +---+ +---+ +---+ |
| | -ERR | | | | -ERR |
| V | V | | |
+<-------------+ | Abort | | |
| V V V |
| +<---------------+-------------------+ +----->+
| V
| +---+ +---+
| | | RSET | | +OK
+----->| C |------>| S |----->+
| | | | | |
| +---+ +---+ |
| V
+<----------------------------+
| ^
| +---+ +---+ |
| | | NOOP | | +OK |
+----->| C |------>| S |----->+
| | | |
+---+ +---+

Reynolds [Page 5]

if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.

RFC documents can be found at I.E.T.F.

Relevance System Copyright © 2002 Spectrum WorldResearch
other technical nosh by ServerMasters Corporation
collaboration of BobX