From ZaInternetHistory

1       swf 9 73; sj y                                  MAIL013
                              UCT Addressing Issue
                                  14 March 1989
        The University of Cape Town and Rhodes University are working
        towards effecting an email link between the UCT HP computer and
        the RU Tower.  Both computers run Unix, and therefore the
        protocol that will be used is uucp.
        This email link will make UCT accessible to the RSCS network
        that exists at the moment.  RU will act as a gateway for UCT.
        When UCT find other methods of linking into the RSA email
        network, the situation will be reviewed.
        The RSCS Network Address Space
        The current RSCS email address space is very simple.  All that
        is required to send mail is to know the mailbox name and the
        name of the host where the mailbox resides.  The route taken by
        the message is totally hidden from the sender.  A Network
        Controller sets this up when he installs the RSCS package.
        Some examples are:-
                Person          Email Address
                ------          -------------
                Vic Shaw        x034601@csirvm
                Philip Welman   rkdpdbw@pukvm1
                Mike Lawrie     ccml@rures
        It is desireable (if not essential) to make the addressing style
        consistent within any network.  This is emphasized in RFC 886
        (Messager Header Munging).  So, the UCT address space as seen
        from an RSCS host (eg CSIRVM) should be of the form:-
        The UUCP Address Space
        Within the Unix world, addresses are specified in the form of a
        path, where each host in the path is mentioned explicitly.  The
        sender must know (and specify) the route that the message takes.
        Also, the order is reversed, the basic form being:-
        Suppose that a message must travel from host UCTCS via UCTHP to
        USER at RUTOWER.  The address that the sender specifies would
        Because of this format, these addresses are called 'bang path'
        addresses.  (The "!" is known as a bang, presumably from bang!)
        Assumed Network Configuration
        In order to give some specific examples, it is assumed that the
        network looks like this:-
        +-------+       +-------+       +-------+       +-------+
        |       |       |       |       |       |       |       |
        | UCT01 |<----->| UCTCS |<----->| UCTHP |<----->|RUTOWER|
        |       |       |       |       |       |       |       |
        +-------+       +-------+       +-------+       +-------+
        UUCP World                                          |
        = = = = = = = = = = = = = = = = = = = = = = = = = = | = = = = = =
        RSCS World                                          |
                                       ##########       +-------+
                                      #  RSCS    #      |       |
                                      #  Network #<---->| RURES |
                                      #          #      |       |
                                       ##########       +-------+
        Addressing a UCT User from the RSCS World
        The only way that the VM Notes system appears to be able to
        address a mailbox is to use the form:-
                        user@host  {Typed as 'user at host'}
        Therefore, at all of the RSCS hosts, a user on any of the UCT
        hosts must be addressed in this form.
        The RSCS routing tables on all RSCS hosts must be updated to
        show that all of the UCT hosts lie 'beyond' the Rhodes host
        known as RURES.  This will cause all UCT mail to accumulate at
        RURES.  RURES will then forward the email to RUTOWER, which will
        convert the address to be the correct bang path.  A table of the
        UCT configuration will be stored in RUTOWER.
        A similar procedure is working on RURES at the moment, using the
        Fidonet link.  There is therefore no major adaptation of any
        software, nor any process that needs to be proven.
        Addressing an RSCS User from a UCT Host
        The view from any UCT host is that the RSCS user is one hop
        further on from RUTOWER.  Thus, at host UCT01, the address of
        Vic Shaw would be
        For each UCT host 'closer' to RUTOWER, so the corresponding path
        is shorter.  From UCTHP, that address becomes:-
        The conversion from the bang path to the domain style will be
        done in RUTOWER before the email is forwarded to RURES.
        Natural Extensions
        This gateway is readily extended to include any other Unix
        hosts.  All that need be done is to adjust the tables in
        RUTOWER.  The comms link used by RUTOWER is X.28, via a Micom
        PAD.  This is driven by a script, to cause it to establish a
        connection with UCTHP.  There should be very little trouble to
        make it connect to any other X.28 number.
1       Points for Clarification
        1.  The RU Tower will in all likelihood be called RUCS01, not
        2.  What will the UCT hosts be called?
        3.  Can RUTOWER do a scripted logon to the Cyber, and transfer
        email from the Cyber relay area to itself, and do the transfer
        in the opposite direction and issue batch MAIL commands?
        4. Should the addressing as specified by a UCT user be
        This latter might allow a later consistency (Jacot, please
        expand on this).  The former is shorter to type, and is quite