Document: FSC-0064
Version:  007
Date:     10-May-1992

                InterDomain Message Identification, Gating,
                      Reply Linking and Addressing
                             Jamie Penner

Status of this document:

     This FSC suggests a proposed protocol for the FidoNet(r) community,
     and requests discussion and suggestions for improvements.
     Distribution of this document is unlimited.

     Fido and FidoNet are registered marks of Tom Jennings and Fido

               Copyright (C) 1990, 1991, 1992 by Jamie Penner
                           All Rights Reserved

                     Originally written:  Sept 3, 1990
                        Revised:  November 12, 1990
                          Revised:  June 23, 1991
                         Revised:  August 26, 1991
                        Revised:  January 22, 1992
                        Revised:  February 4, 1992
                        Revised:  February 12, 1992

Use of this proposal is encouraged and permitted by the author without
further notification in any software which is being written to conform
to FTSC specifications.

Suggestions and discussion are strongly encouraged.   The author may be
reached at:


Echomail Basics:

        All echomail passing through an interdomain echomail gateway
        must have all information in the message header changed to
        reflect the proper address of the domain in which the messages
        are entering.   The PATH and SEEN-BY lines should also reflect
        these changes with only the SEEN-BY line containing any
        information from the domain previous.   This information shall
        be the single address of the system passing the mail to the
        gateway system.    In addition, all gateway software should
        recognize, by the message itself, whether it has EVER passed
        through the gateway in the past.   CRC records, SEEN-BY lines,
        PATH lines and MSGID lines are not sufficient for this purpose
        as most systems purge recorded logs of this info after a given

InterDomain Echomail/Netmail Flags:

^ADOMORG: usr.nme@[!][p.f.n.z.]network[.nid][[#nodelist_name][#point[x]]
^ADOMDES: usr.nme@[!][p.f.n.z.]network[.nid][[#nodelist_name][#point[x]]

        These lines would be a complete domain signature for any user on
        any system in any FTN network.

        The DOMORG line would be the actual origin information of the
        user and system sending the information.

        The DOMDES line would be the actual destination information of
        the recipient user and system.

        There are essentially two variations to the domain signature.
        The ! immediately following the @ denotes a Type B, otherwise
        defaulting to Type A.

        Type A:

                e.g.  jamie.penner@f1025.n153.z1.fidonet

                This has the complete FTN information needed for any
                processor to send the message.

        Type B:

                e.g.  jamie.penner@!signet.admin#ic.signet

                The ! immediately preceeding the network signifies that
                no FTN information is available but the information
                after the # will give the name of the system as denoted
                in the nodelist for that network.   This way, processors
                can be designed in a fashion that they can look up the
                system name.    Should this be going to a point, the
                domain may be:


                If I have two points and I want to send it to a
                different point, I might use:


                The domain identifier in a Type B signature can be
                further used for further locating a system if needed.
                In both signature types, the nid (network identifier) is
                optional (eg or signet.admin - only the
                first field actually identifies the network name).
                This information is completely dependant upon each
                domain.   For example I might send this:


                This kind of structure would get the message to the
                right system.   If there was two of the same system in
                Region 331, I could use:


        This format of domain signatures is provided solely for
        compatibility purposes to provide software developers with a
        platform on which they can structure new programming techniques
        and can be used in conjunction with the other flags as laid out
        in this document.

 # GateOrigin: zzz:NNN/nnn.ppp@dmn    (note leading space)

        This line is currently inserted into all stripped down echomail
        passing through interdomain gateways by GateWorks.   This allows
        the message overhead to be cut down by properly replacing the
        origin line for users to read in the text yet, not creating a
        second full originline.   This line shall be added immediately
        before the tearline with a single blank line following it.

        e.g.    # GateOrigin: 24:24/0.0@signet

^AGATECHK: zzz.NNN.nnn.ppp [zzz.NNN.nnn.ppp] [zzz.NNN.nnn.ppp]
        Any echomail passing through a particular gateway should have
        this line inserted at the beginning of the message text.
        Everytime the message passes through another echomail gateway,
        the address would be added to the line.   This way, if a message
        passes back through with the same ID, it is a known duplicate
        and can be vaporized.

        e.g.    ^AGATECHK: 8.8.7001.0

^AMSGORG: <originating-address> <originating-ID>

        The MSGORG line keeps a standard original address and message id
        in the message for reply, identification, dupe checking, and
        origination purpose.    This line would vanish and be replaced
        with the necessary lines if passed through a gateway.

        e.g.    ^AMSGORG: 24:24/0.0@signet 0123456789abcdef

        The originating ID is no different than other 16 bit IDs being
        generated.   It must be unique in a sense that no other message
        originating from that system will have the same number (at least
        within a short time span).

^AGATEWAY: <zonegate-address>

        This field is inserted by the packer.   The user-defined
        zonegate fields give the message its destination to the zonegate
        and may be routed through whatever channels to get there.

        e.g.    ^AGATEWAY: 1:153/

^GRPLY: <zonegate-address> <originating-address>

        When replying to a message, this line would be looked up so as
        to find the actual message destination and give the system its
        zonegate information.    If the message passes through a
        gateway, the MSGORG line would be removed upon insertion of
        this line.

        e.g.    ^AGRPLY: 1:153/ 24:24/0.0@signet

An example echomail message from 24:11/7777.0@signet across the domain
to 1:153/85.0@fidonet should read:

To: Bill Herringshaw, 1:153/85.0@fidonet
From: Jamie Penner, 1:153/1025.0@fidonet
Subject: Testing
^AGRPLY: 1:153/1025.0@fidonet 24:11/7777.0@signet
^ADOMORG: jamie.penner@f7777.n11.z24.signet.admin
^APID: RA 1.01

Hi Bill, just testing out this new software

 # GateOrigin: 24:11/7777.0@signet

 --- GateWorks v4.00a
* Origin: Home of GateWorks!! (1:153/1025.0)
SEEN-BY: 24/0 153/1025
^APATH: 153/1025

An editor programmed to handle these fields would recognize GRPLY line
and know that the message had passed through a gateway.    An echomail
reply would simply pass through the gateway.   If a netmail reply was
required, this would be the reply message:

To: Jamie Penner, 24:11/7777@signet
From: Bill Herringshaw, 1:153/85.0@fidonet
Subject: Testing
^AGATEWAY: 1:153/1025.0@signet
^AGRPLY: 24:24/0.0@signet 1:153/85.0@fidonet
^ADOMDES: jamie.penner@f7777.n11.z24.signet.admin

> Hi Bill, just testing out this new software

Got it here!

via InterMail @ 24:24/0.0@signet, 17:23:17  22 Jan 92

The mailer and/or packer would check for the GATEWAY flag and route the
message through that gateway.

Under this method of flags, all systems in all domains should have
access to the ability to reply via netmail to a system in a different
domain.    In addition, by following this specification, all interdomain
echomail should be clean and troublefree.   This eliminates the need for
some of the other ^A lines being used.

It is the intention that all addresses in these flags may use the 5d
addressing scheme, or either of the Type A or B domain signatures.   The
software should be written to determine the type of address used and
manipulate the situation accordingly.

The following list of software may be incomplete but lists all software
currently available or under development using this spec:

        GateWorks v4.00