Document: FSC-0043
Version:  002
Date:     30-Aug-90

     Some Hints on Recognizing Control Lines in FidoNet(r) Message Text
                              1990 August 30

Status of this document:

This FSC contains information of value to the general FidoNet(r) community.
Distribution of this document is subject to the restrictions listed in the
copyright paragraph below.

Fido and FidoNet are registered marks of Tom Jennings and Fido Software.

Copyright 1989-90, Randy Bush.  All rights reserved.  A right to distribute
only without modification and only at no charge is granted.  Under no
circumstances is this document to be reproduced or distributed as part of or
packaged with any product or other sales transaction for which any fee is
charged.  Any and all other reproduction or excerpting requires the explicit
written consent of the author.

Implementors have had problems interpreting message text, both in netmail and
echomail.  While the clues are usually to be found in some doucment or another,
there seems to be a need to collect hints for some confusing aspects.  This
informal documents attempts to address that need.

Filter out all <lf>s and 'soft' <cr>s and <lf>s.  They are surplus and will
only confuse the rest of your code.

All control lines have their sentinels at the beginning of a line.  [ Note
that an * Origin: line has a leading significant blank. ]

Do not process quoted control lines or control sentinels preceeded by blanks,
tabs, ...

If you become confused, then bounce or sidetrack the message to a hold area
for human intervention.  Don't try to rescue the situation.  None will notice
when you succeed, and many will flame whan you fail.

A message is either netmail or echomail.  I.e. no ^aINTL, ^aFMPT, or ^aTOPT
controls should be found or generated when there is an AREA: line or when in an
echo area. Thus, echomail can not be routed across zones, but this is not a big

Private netmail replies to echomail are netmail, i.e. may have ^aINTL etc.,
and may not have AREA: line, SEEN-BY:, or ^aPATH: lines.  They may have a tear
line and an origin line.

^aEID lines are as in Opus 1.03.  Other forms are not to be generated, and,
if found, may be safely disgarded.

An AREA: line must be the first non ^a line in the text.

The echomail control info is a four-part package at the end of the text.  It
should not be, but occasionally is, followed by one or more ^a control lines.
The four parts of an echomail trailer are:

  o a tear line, "---" and some very short text identifying the original echo
    processor.  Eg.
        --- Brag 3.14

  * note that some internetworking gateware may place a # Origin: line between
    the tear line and the * Origin: line to indicate the true other network
    address, whatver that may be.  The content of a # Origin: line is free to
    be specified by the other network(s).  An example might be as follows:
         # Origin: Political Statement (FishNet:914@201)

  o one * Origin: line, being " * Origin: " ends in "(" [Z:] N "/" N [.P] ")"
    of FidoNet node of origin or the gate from FidoNet to another network
         * Origin: <signature> (1:105/301)

  o as many SEEN-BY: lines as necessary, each being "SEEN-BY:" followed by one
    or more
        " " <net> "/" <node>
    sequences.  Note that SEEN-BY: lines do not end in <space>.

    The net/node numbers in SEEN-BY: lines are sorted net major.  Within a
    single SEEN-BY: line, net numbers are sticky, so the N/N is usually
    abbreviated to N, Eg. 
        SEEN-BY: 105/6 10 15 16 27 41 42 300 301 141/42 491

  o as many ^aPATH: lines as necessary, each being <ctrl-A> "PATH:" followed
    by one or more
        " " <net> "/" <node>
    sequences.  The N/N in ^aPATH: lines are specifically not sorted.  Net
    numbers are also sticky in ^aPATH: lines, eg.
        PATH: 105/301 6 42

Remember that traffic costs much money, and do not create text unnecessary to
FidoNet as a whole.

I did not invent this, so don't blame me.  I'm just trying to write it down.

And, lastly, try not to be inventive.  While the free-form syntax of this
embedded stuff does provide fleibility and power, it also leaves a lot of room
to make disgusting messes.  Compromise, cooperation, and a minimizalist touch
are essential.

Randy Bush
FidoNet: 1:105/6 1:105/42
Internet:    randy@m2xenix.uucp
uucp: { uunet, qiclab, bucket }!m2xenix!randy


Fido and FidoNet are registered marks of Tom Jennings and Fido Software.