XCLN: POP3 Supported Command Set for Exchange Server 5.0

• Microsoft Exchange Server, version 5.0

SUMMARY

POP3 is a very simple and limited protocol. It has a set of approximately 11 commands, 10 of which are supported by Microsoft Exchange Server.

To test a POP3 connection to a Server, the user may telnet to port 110 of the POP3 Microsoft Exchange Server computer and execute any of the following commands.

MORE INFORMATION

Listed below are the commands along with the functionality that each command provides.

Command    Description

USER       Used to specify the name of the user you wish to logon as.

           For TR1, it can be specified in the form of either:

              USER <username>

           -or-

              USER <domain\username>

           Additionally, if the mailbox name for the user logging on differs
           from that of the username, the log on may be stated in the form of:

              USER <domain\username/mailboxname>

PASS       This is the Windows NT domain password of the user who is logging
           on.

           Usage:

              PASS password

LIST       Used to list messages and their combined size. For example,
           invoking the LIST command with no parameters will return 2 +OK
           messages (320 octets). This means that there are two messages
           in the user's mail drop taking a total of 320 octets of space.
           To see an individual message simply type:

              LIST <N>

           Where <N> is a number between one and the number of messages 
           originally returned by the LIST command.

QUIT       Quits the current telnet session and deletes any messages
           marked for deletion.

UIDL       Returns the Unique ID Listing for a message. This command
           invoked in the form of either:

              UIDL

           -or-

              UIDL <N>

           Where <N> is the message number of the UIDL that the user want to 
           view.

           Microsoft Exchange determines this unique value in the following 
           fashion:

              The BASE64 value of the 64-bit Message ID and then the 128 GUID 
              for that message. If the command is invoked without arguments
              then a numerical listing of all messages and their associated
              UIDLs is displayed.

APOP       Not Supported. APOP is an alternative method of authentication.
           This is one of the optional POP3 commands.

RETR       Used to Retrieve a message from the server.

           Usage:

              RETR <N>

           Where <N> is a number between 1 and the last number returned by the
           LIST command. This command may not be used to retrieve a message
           that has been marked as deleted.

STAT       The STAT command is similar to the LIST command in that the
           server will return the number of messages in the Mail drop
           along with the total space (in octets) that those messages
           occupy. However, this is all the information returned by this
           command. To display messages, either the RETR or LIST commands
           must be invoked.

DELE       This command is used to delete a message. It does not actually
           delete the message but simply sets a delete flag. The message is
           actually deleted when the client gracefully breaks the
           connection to the server using the QUIT command. In the case
           where there is a crash or immediate connection termination by
           the client, the messages are not deleted.

           Usage:

              DELE <N>

           Where <N> is the number of the message provided by the LIST command.

NOOP       A Null or NO OPeration. In this case, the server does nothing.

RSET       Used by the client to reset the state of messages marked for
           deletion.

TOP        This command is used to display both the header for a message
           and a given number of lines for that message. This command is
           used in the form of:

              TOP <X> <Y>

           Where <X> is the message number the user wants to view and <Y> is
           the number of lines in that message to be displayed.

           The server should return the headers for the message followed by a
           blank line and then the Y number of lines for that message.

AUTH       This is an IMAP4 command that is part of the POP specification
           from RFC1734. It allows for the use of alternative IMAP4
           authorization techniques.

For more information on POP3, please refer to RFC 1725, RFC 1734 and RFC 1939. You can locate these and other RFCs at the InterNIC Web site at the following address:

   http://www.internic.net/ds/rfc-index.html