RFC 918 (rfc918) - Page 1 of 5

Post Office Protocol

Alternative Format: Original Text Document
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Network Working Group                                     J. K. Reynolds
Request for Comments: 918                                            ISI
                                                            October 1984


                          POST OFFICE PROTOCOL


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.

Introduction

   The intent of the Post Office Protocol (POP) 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].

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

The Protocol

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

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








Reynolds
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