Columbia Kermit/kermit.zip/hostmode/hostmode.txt

Text File | 2020-01-01 | 33KB | 796 lines

KERMIT 95 HOST MODE PROPRIETOR'S GUIDE

  ---   PREPUBLICATION DRAFT   ---

  Copyright (C) 1996, Frank da Cruz and Christine M. Gianone.
  All rights reserved.

Most recent update: February 8, 1996.
Applies to: Kermit 95 1.1.3, Host Mode script version 1.00.


CONTENTS

  1. INTRODUCTION
  2. WHAT HOST MODE IS FOR
  3. THE HOSTMODE MANAGEMENT PROGRAM
  4. CONFIGURATION
  5. USER IDs
  6. LOGS
  7. MESSAGES
  8. STARTING AND STOPPING HOST MODE
  9. SUMMARY OF FILES
 10. IDEAS FOR IMPROVEMENT


1. INTRODUCTION

The "host mode" feature described here can be used with Kermit 95 1.1.3 and
later, allowing people to dial up or Telnet to your PC and transfer files
within a secure restricted environment.  Kermit 95's host mode is implemented
entirely in the Kermit script language, and executed by Kermit itself.  You
can find all the scripts in the Kermit 95 SCRIPTS subdirectory as HOST*.KSC.

The host-mode scripts include the host-mode user interface, a host-mode
management program for the PC owner, and some others, plus some configuration,
database, and documentation files.  There is also a new program, K95D.EXE, the
"Kermit 95 Daemon", that handles incoming TCP/IP connections and starts up
subprocesses to handle them.

For a detailed explanation of Kermit's script programming language, refer to
Chapters 11-13 of "Using C-Kermit", as supplemented by DOCS\CKERMIT.UPD.

Documentation for host-mode users is in two separate files:

  USERS\HOSTMODE.TXT  -  A short help file
  PUBLIC\HOSTUSER.DOC -  A more detailed user guide

The host-mode manager's guide is this file that you are reading.

In this document, filenames are all relative to the Kermit 95 directory, even
though you can configure Kermit 95's host mode to use any other directories of
your choice.  So, for example, if you have installed Kermit 95 in D:\K95,
then:

  USERS\HOSTMODE.TXT

refers to:

  D:\K95\USERS\HOSTMODE.TXT

Kermit 95's host mode feature is entirely self-contained and does not make any
use at all of the Windows 95 (or NT) Registry or Windows 95/NT user IDs or
passwords.  Therefore it is not to be run as a Windows NT Service under the
Service Manager.

When you use host mode, you become what amounts to the manager of a multiuser
computer system.  As such, you need to understand how the system works before
you can provide good and reliable service to your users.  So before you jump
right in to running the Kermit 95 host, please read the following sections
about security, configuration, user ID management, logs, and messages.


2. WHAT HOST MODE IS FOR

Windows 95 is not a multiuser operating system in the traditional sense that
it can be dialed up and logged in to by ordinary terminals or terminal
emulators, nor that it embodies notions of file ownership and access
permission within the PC's file system.

Yet often, the owner of a PC wants to allow other people to be able to dial up
her PC from different types of computers and upload or download files.
Sometimes even the owner herself needs to do this from a remote location.
This could be done simply by leaving a Kermit server running on the desired
communication port or TCP socket, but in that case the user gets no cues about
what to do.  Also, security is an issue -- if you leave your PC in this state,
anybody who knows the phone number or Internet address can access it and,
potentially, do some damage.

Kermit 95's host mode provides a simple mechanism for access control, and it
gives users an easy-to-use menu.  The functions are limited: upload and
download files within restricted areas, display files, display directory
listings, read and leave messages.  Multiple authenticated users are allowed,
as well as anonymous (guest) access if you (the PC owner) permit it.

Furthermore, there are several levels of privilege, allowing different levels
of access to the file system and to the facilities of the operating sytem.

Cast of characters:

PROPRIETOR
  The PC owner, or "proprietor", is the person who grants access to users by
  giving them IDs, and the one who configures host mode, and who starts and
  stops host most from the PC's console (keyboard and screen).  This document
  is for you, the proprietor.

USER
  A "user" is someone who accesses the PC from a remote location via Telnet or
  dialup, and who logs in and accesses the PC only via the host-mode menus,
  providing a username and a password.  The Kermit 95 host can have any number
  of distinct users, plus a "guest" username that can be logged into by
  anybody without a password if the PC owner wishes.

GUEST
  An anonymous user who can log in without a password, if you allow it.
  A guest never has any privileges.


3. THE HOSTMODE MANAGEMENT PROGRAM

Kermit 95 host mode comes with a management program to make it easy for
the PC owner (proprietor) to start host mode, manage the configuration,
manage user IDs, send and read messages, and so on.

To run the management program, enter a console ("DOS") window and type:

  hostmode

NOTE: "hostmode" is simply a Batch program (hostmode.bat) that starts
K95.EXE and has it execute the host-mode management script, HOSTMODE.KSC.

You will see the following menu:

--------------------------------------------
K-95 Host Mode Management

 1 - Start host mode
 2 - Display configuration
 3 - Change configuration
 4 - Save configuration
 5 - Read messages from users
 6 - Leave a message for a user
 7 - View/edit current greeting message
 8 - Post a new greeting message
 9 - Manage user database
10 - Help
11 - Exit

Your choice:
--------------------------------------------

 1 - Start host mode

This option guides you through starting a host-mode listener.  You may choose
to start a listener for Telnet connections or for dialup connections.  In each
case, the relevant parameters are displayed for you and you can choose whether
to proceed, or to change the parameters.  For Telnet, the only parameter is
the socket number.  For dialup, the parameters are the dialup device (port)
name, the speed, and the modem type.  If you wish to change any of these
parameters, return to the main menu and choose "Change configuration", and
then come back to "Start host mode".

If you wish to use a TAPI device (in Windows 95, or Windows NT 4.00 or later),
specify the port as "{TAPI name_of_tapi_device}". That is, the word TAPI
followed by the name of the desired TAPI device, but with each space replaced
by an underscore, all enclosed in braces, for example:

  {TAPI US_Robotics_Sportster_28800}

And specify the modem type as "TAPI".

Direct serial connections are also offered, but these are a bit tricky.  In
particular, you have to be very sure you've got a true null-modem connection
that cross-connects the receive and transmit wires, the DTR and CD wires, and
the RTS and CTS wires.  The latter is important or else flow control won't
work and there could easily be large amounts of data loss, exhibited as
fractured screens and file transfer failures.

 2 - Display configuration

This lists the current host mode configuration -- each variable and its
assignment.

 3 - Change configuration

You are prompted for each configuration variable.  The current value is shown
in [brackets].  If you don't want to change it, just press the Enter key.  If
you do want to change it, type in the new value and then press the Enter key.
You can use Backspace (delete character), Ctrl-W (delete word), and Ctrl-U
(delete line) for editing.  After entering the new value, you are given a
chance to change your mind.  After all the variables have been processed, you
are returned to the main menu, but the configuration data is not saved, so you
still have other chances to change your mind.  (Don't worry, if you try to
exit without saving the configuration, you'll be warned.)

 4 - Save configuration

Saves the current configuration in the HOST.CFG file.

 5 - Read messages from users

If users have sent you messages, this will display them for you.

 6 - Leave a message for a user

This lets you compose and send a message to a particular user.  Whenever a
user has messages waiting, it says so in the user's main menu.  Thus, even if
you send a message to a logged in user, they can find out about it and read it
right away.

 7 - View/edit current greeting message

This lets you view the current greeting message that all users see when
they log in and edit it if you want to.  It just runs Notepad on the message
file.

 8 - Post a new greeting message

This lets you post a new greeting message for all users.

 9 - Edit user database

This is the user ID management feature: add, remove, and change user IDs
and passwords.  Explained in section 5.2.

10 - Help

Displays a brief help message.

11 - Exit

Exits back to the console window "DOS" prompt.


4. CONFIGURATION

Your host-mode configuration is governed by a plain-text configuration file,
HOST.CFG, in Kermit 95's SCRIPTS subdirectory.  The configuration variables
are listed below, along with their default values -- that is, the values they
have if you don't change them.  All the various scripts that make up host mode
read this file to get the information they need.

You can change the default configuration by editing the HOST.CFG file with a
text editor like EDIT or NOTEPAD or perhaps more conveniently, by using the
"Change configuration" option of the host-mode management program, HOSTMODE.
The standard configuration file is shown here in its entirety:

sessions=1                             ; Maximum simultaneous Telnet sessions
maxusers=100                           ; Maximum number of user IDs
inactivity=1200                        ; Inactivity limit (seconds)
logintime=300                          ; Inactivity limit during login
anonok=1                               ; Anonymous logins OK (0 = not OK)
logging=1                              ; Logging enabled (0 = skip logging)
dlincoming=0                           ; Downloads OK from INCOMING directory
msgmax=200                             ; Longest message size (lines)
hostport=3000                          ; TCP port to listen on
comport=                               ; Communication port for dialins
comspeed=                              ; Speed for communication port
modem=                                 ; Type of modem on communication port
protocol=kermit                        ; Default file transfer protocol
xfermode=binary                        ; Default file transfer mode
owner={THE PROPRIETOR}                 ; For user's MESSAGE FROM... message
herald={Welcome to K-95 Host Mode}     ; Main menu title
public=\v(startup)PUBLIC               ; Publicly readable directory
incoming=\v(startup)INCOMING           ; Publicly writeable directory
logdir=\v(startup)LOGS                 ; Directory for proprietor's logs
usertree=\v(startup)USERS              ; Root of user directory tree
tmpdir=\v(startup)TMP                  ; Directory for temp files
userfile=\m(_usertree)/HOST.USR        ; User database file
greeting=\m(_usertree)/GREETING.TXT    ; Message/greeting text filename
helpfile=\m(_usertree)/HOSTMODE.TXT    ; Host-mode help file
msgfile=\m(_usertree)/MESSAGES.TXT     ; Messages for proprietor

Now, in more detail:

sessions=4
  The maximum allowed number of simultaneous incoming TELNET sessions.
  Strictly speaking, the number is either 1 or "more than one".  If it is
  1, then we simply run host mode in a loop: wait for a connection to come
  in, have a session, close the session, wait for the next connection to
  come in, and so on.  If SESSIONS is greater than 1, we use a special
  "daemon" to wait for incoming connections and spawn new, possibly concurrent
  sessions.  IMPORTANT: Only Microsoft TCP/IP allows multiple sessions.  If
  you attempt to set SESSIONS greater than 1 with Trumpet Winsock or FTP
  OnNet, it won't work.  The default maximum of 1 session should work with
  all varieties of TCP/IP.

maxusers=100
  The maximum number of users allowed in the user database.

inactivity=1200
  Inactivity limit in seconds.  A logged-in user who doesn't type anything in
  this amount of time is logged out and disconnected.  This prevents idle
  users from tying up resources on your PC.

logintime=300
  Inactivity limit in seconds in effect during the login process.  People
  who don't type anything in this amount of time while at the Username or
  Password prompt are logged out and disconnected.

anonok=1
  This means that anonymous (guest) logins are permitted.  Change the 1 to 0
  if you only want known users (from your HOST.USR file) to log in.

logging=1
  This means you want to keep logs of the activities of your host-mode
  users (see Section 6).  Change 1 to 0 if you don't want to keep logs.

dlincoming=0
  This means it is not OK for users to download from the INCOMING directory
  nor to type files or get directory listings from it.  If you want to
  permit this type of access, change 0 to 1.  But this carries certain risks
  (e.g. if they upload copyrighted material illegally, then you might be
  held responsible for its further distribution).

msgmax=200
  Maximum length (in lines) for messages sent by the user to the proprietor
  or vice-versa.

hostport=3000
  The TCP port to be used while listening for incoming Telnet sessions.

commport=
comspeed=
modem=
  Communications parameters to be used when waiting for incoming modem
  calls.  If these are left blank, the values from your K95CUSTOM.INI
  file are used.

  If you wish to use a TAPI device (in Windows 95, or Windows NT 4.00 or
  later), specify the "commport" as "{TAPI name_of_tapi_device}". That is,
  the word TAPI followed by the name of the desired TAPI device, but with
  each space replaced by an underscore, all enclosed in braces, for
  example:

    commport={TAPI US_Robotics_Sportster_28800}

protocol=kermit
  The default file transfer protocol.  The other choices are zmodem,
  ymodem, ymodem-g, and xmodem.

xfermode=binary
  The default file transfer mode.  The other choice is text.

owner={THE PROPRIETOR}
  This is what is shown to users who receive messages from you.  Replace
  this by your name, your company's name, or whatever you like.  Braces are
  needed if the value contains any spaces.

herald={Welcome to K-95 Host Mode}
  This is the title shown at the top of the main menu screen.  Replace it
  with anything you like, up to about 50 characters.  Braces are needed
  if the value contains any spaces.

public=\v(startup)PUBLIC
  This is the directory that all users can CD to and download from,
  but can't upload to.  In other words it is the public "read only"
  directory, intended for you (the PC owner) to distribute files to
  your users.  NOTE: \v(startup) stands for the directory that Kermit 95
  was started from -- normally the directory you installed it into.

incoming=\v(startup)INCOMING
  This is the directory to which all users are allowed to upload files,
  but which they can't download from or see directory listings of.
  In other words, it is the public "write only" directory, intended for
  your users to send files to you.  Optionally, you can configure this
  directory to also allow your users to download from it -- see the
  variable _dlincoming above.

logdir=\v(startup)LOGS
  This is the directory where log files are kept (see below).

usertree=\v(startup)USERS
  This is the root of the user directory tree.  So, for example, if your
  Kermit 95 directory is D:\K95, and you have a host-mode user named Olga,
  her personal directory will be D:\K95\USERS\Olga.  You can change this in
  case you want to put your host-mode users someplace else.

tmpdir=\v(tmpdir)
  Name of a directory that Kermit 95 can use for writing temporary files.

helpfile=\m(_usertree)/HOSTUSER.DOC
  Help text that is displayed if the user asks for help.  This is a
  short plain-text file that you can modify if you wish.

greeting=\m(_usertree)/GREETING.TXT
  A short text file which, if it exists, is displayed every time each
  user logs in.  You can create it with a text editor, or use the HOSTMODE.KSC
  script to create it for you.

msgfile=\m(_usertree)/MESSAGES.TXT
  Name of the file in which messages from users to the proprietor are placed.

userfile=\m(_usertree)/HOST.USR
  This is the user database file, as described above.

5. USER IDs

As distributed, HOST.KSC requires users to log in with a user ID and password.
A user ID gives the user access to a private directory with full read/write
access.  Guest (anonymous) users, if allowed, do not have a private directory.

A failed login causes a three-second pause.  Three failed logins cause the
host script to hang up the connection.  All logins, failed logins, and actions
are recorded to a file.

5.1. STRUCTURE OF USER IDs

User IDs should be composed of letters and/or digits, and should not contain
spaces, underscores, backslashes, or other non-alphanumeric characters.

Kermit 95's host mode allows users access to three different directories:

 1. The user's own private directory, to which the user has read/write
    access, but which other users can't access.

 2. The PUBLIC directory, to which all users have read access only.

 3. The INCOMING directory, into which all users can send files, and, if you
    permit it, from which all users can also retrieve files.

(In addition, users with "CD Privilege" can also access any (ANY) other
directory on the system; more about this later.)

Regular unpriviledged users can switch among these three directories, but they
can't go anywhere else -- not for reading or writing files, not for getting
directory listings.  If a file is uploaded containing a pathname, the pathname
is stripped upon receipt, preventing users from being able to place or
overwrite files in other other areas.  Similarly, pathnames are stripped from
filenames given by the user in download requests, thus restricting their
access to their current directory.

5.2. MANAGEMENT OF USER IDs

IDs are created only by the owner of the PC.  An ID is associated with an
entry in the user database, normally USERS\USERS.DAT (you can change this in
the configuration, if you want to), which is a plain-text ASCII file
consisting of entries (lines) of the form:

  username_encryptedpassword_privileges_name_address_phone_email_

in which each field is terminated by an underscore, for example:

  jrd_6840DF9017F59B67_0_Joe R. Doupnik_Utah State [e-mail]_

The encrypted password can be created or modified only by using the tools
provided -- not with a text editor or any other tool, because the encryption
method is internal to Kermit 95.  The encryption method should be secure
enough that no harm would be done if the USERS.DAT file fell into unfriendly
hands, but of course there can be no guarantees.  In any case, the hostmode
system is set up so that UNPRIVILEGED hostmode users will not have access to
this file.

Adding a user to the database is sufficient to create the user ID.  The host
script creates the user's directory automatically the first time the user logs
in successfully.

To manage user IDs, select "Manage user database".  This presents you with a
new menu that looks like:

  User database management functions...

  Database filename: USERS/USERS.DAT - Not loaded
  Current user:      (none)

   1 - Load user database
   2 - Display user database
   3 - Look up a user / set current user
   4 - Add a new user
   5 - Remove current user
   6 - Modify current user
   7 - Save user database
   8 - Remove lock
   9 - Return to main menu

  Your choice: _

Before you can do anything else you must load the user database (item 1).
If no user database exists yet, item 1 reads "Create user database".  In
either case, select item 1 first.

Item 2 lets you look at the user database -- the literal contents of the file.

Item 3 lets you look up a particular user.  You are prompted for the user's ID
or name (either one will work).  If the user's entry is found, this becomes
the "current user", which is the one affected by Remove and Modify selections.
When a user is selected in this way, her ID is displayed in the Current User
field above the menu.

Item 4 lets you add a new user.  You are prompted for each field separately:
user ID, password, privilege level, user's name, address, phone number, and
email address.  All but the ID, password, and privilege level are optional.
When you have entered the information, it is displayed for you and you are
asked for permission to create the user ID, and if you give it, the ID is
created.  NOTE: The user ID can not actually be used until you save the
database (Item 7).

Item 5 removes the current user ID (obtained from Item 3) from the database.
The entry is displayed, your permission is requested, and if you give it, the
entry is removed from the database.  However, the user's directory and files
are not removed.  You can do this yourself by hand -- since it is your PC, you
might want to see what the user has been storing there and decide what to do
with the files.  NOTE: The user ID is not actually removed until you save the
database (Item 7).

Item 6 can be used to change the password and/or the privilege level of the
current user.  NOTE: These changes do not actually take effect until you save
the database (Item 7).

Item 7 saves the database, activating any changes you have made to it.

Item 8 unlocks the user database.  This will be necessary in case a host-mode
session left a stale lock behind; for example, if they became disconnected
while changing their password.  You can also remove the lock at the DOS
prompt, simply by deleting the USERS.LCK file in the USERS directory.  You
can also type this file -- it contains the user ID of the user who created
the lock.  The timestamp on the file shows when it was created.

Item 9 returns you to the main menu of the hostmode program.

5.3. PRIVILEGES

There are several levels of privilege:

 0 - No special privileges.  Users with this privilege level are restricted
     to their own directory, plus the INCOMING and PUBLIC directories.  It
     should be safe to give this level or privilege to anybody.  GUEST users
     always have 0 privilege and, in addition, do not have a directory of
     their own.

 1 - CD privilege.  This lets the user CD to any directory on the computer.
     This should be given only to persons that you trust utterly and
     completely yourself, and whom all of your other host-mode users can
     trust as well.  This privilege allows the user to download any file at
     all, to upload any file into any directory, possibly overwriting
     critical system files or sensitive personal ones, including the host
     mode user database, perhaps altering privilege levels of other other
     users.  We recommend that this privilege be granted only to the PC's
     owner and not to any other users.

 2 - DOS privilege.  This lets the user execute DOS commands.  It implies
     and includes CD privilege, since there is no control over DOS commands,
     their operands, and what they can do.  All the previous cautions apply,
     and then some.


6. LOGS

All user actions are written to the hostmode window and, unless you change
things, also written to a log file in Kermit 95's LOGS subdirectory.  The log
file name for each session should be unique:

  <user>_<date>_<time>.log

for example:

  olga_951224_12345.log

where "olga" is the username, the first number is the julian date (yymmdd)
and the second is the time in seconds since midnight.  These logs should be
cleaned out periodically, especially if you have a lot of host-mode users
and/or sessions, otherwise your disk could fill up.

If you don't want to keep log files, see the Section 4 about how to disable
the log-file feature.


7. MESSAGES

You can leave a message that all users will see when they log in (even
anonymous users) in the greeting file.  Use the "hostmode" program to post
messages.

You can also use the hostmode program to leave a private message for a
particular user.

Users can leave messages for you ("the proprietor") via the "Leave a message"
menu entry.  All such messages are appended to a single message file,
MESSAGES.TXT in the root directory of the user tree.  You can read them with
the hostmode program.

All messages produced by Kermit 95 host-mode scripts are in standard e-mail
format:

Date: <date and time message was sent>
From: <username> (or if from you, the OWNER value)
To: <username> (or if a general message, "All")
Subject: <line of text>

<message body...>
.

Each message ends with a period alone on a line, and a blank line separates
the headers from the message body.

All message reading is done simply by putting the message into the "notepad"
editor for you.  It is up to you to dispose of it.  There is no built-in
mechanism for replying to a message -- instead, just choose the "Leave a
message" from the main menu.


8. STARTING AND STOPPING HOST MODE

Using a single copy of the HOSTMODE program, you can run one or more host
sessions simultaneously on any combination of serial communication ports or as
TCP/IP Telnet servers.

To stop a host script, bring its window to the front and type Ctrl-C, and then
"exit" from K-95, which will close any open files, devices, or connections.
If Ctrl-C does not bring you back to the prompt (for example, when waiting for
an incoming TCP/IP connection), then use the mouse to close the window from
its system menu.

By the way, once you interrupt a host script by typing Ctrl-C, the connection
is still open so you can (for example) CONNECT and then type characters which
the client will see on her screen.  You can also use OUTPUT and TRANSMIT and
any other commands to send text to the client's screen prior to hanging up
and/or exiting.

8.1. HOST MODE ON TCP/IP CONNECTIONS

TCP/IP connections are governed by the SESSIONS and HOSTPORT parameters in
the configuration file.

HOSTPORT=3000

This is the TCP port, or "socket", on which the host session listens for
incoming connections.

SESSIONS=1

If SESSIONS is 1, then only one Telnet host session is allowed at a time.
In that case, the HOSTTCP.KSC script is used to wait for incoming connections
and then to run the HOST.KSC script for them.  This method is required for
FTP OnNet-32 and Trumpet Winsock, because these TCP/IP stacks do not allow
socket handles to be shared.

If you are using Microsoft TCP/IP, you can set SESSIONS to 2 (or any number
greater than 1), which allows multiple concurrent sessions.  (The number
doesn't matter -- there is presently no way to limit the number of concurrent
sessions to a particular maximum.)  In this case, the K95D.EXE program is
used to listen for incoming connections and to spawn a host session for each
one.

SESSIONS=1 works with all TCP/IP stacks, and so it is the default.  Numbers
larger than 1 only work with the Microsoft TCP/IP stack.

Users should connect to your PC using a Kermit program that has built-in
Telnet capability: Kermit 95, OS/2 C-Kermit, MS-DOS Kermit, UNIX C-Kermit, VMS
C-Kermit, etc.  They should also enable the APC feature, if they have it,
which allows both uploads and downloads to be automatic.  So if your PC's
hostname were pc.oofa.com, the client Kermit command to make a connection to
your PC would be:

  set terminal apc on
  telnet pc.oofa.com 3000

For testing (under Microsoft TCP/IP only), you can run the host and client
window on the same PC -- tell the client Kermit program to "telnet localhost
3000".

K95D.EXE can also be used for other purposes.  You can run it with a command
line, or with a configuration file.  The command line format is:

  k95d <socket> "<k95 command>"

where <socket> is a socket number (such as 3000) and <k95 command> is one or
more Kermit 95 commands (if more than one, separated by commas), for example:

  k95d 3000 "take scripts/host.ksc, exit"

Note the doublequotes around the K95 commands -- this causes the multiple
words to be grouped together by the Windows shell as a single argument for
K95D.EXE.

If you start K95D.EXE without command-line options, it reads its configuration
files, K95D.CFG, which contains lines of the same form as the command line
arguments, but without the quotes, for example:

  ; This is a comment
  1000  set term echo local, set term newline on, connect
  2000  server, exit
  3000  take scripts/host.ksc, exit

Then, if any connection came in on port 1000, a "chat mode" session would be
started.  Connections coming in on port 2000 would get a Kermit server, and
connections on port 3000 would get a host-mode session.

8.2. HOST MODE ON DIALED CONNECTIONS

The management program uses HOSTMDM.KSC to run the host mode script in a loop,
so whenever a user logs out, Kermit 95 waits for the next incoming phone call.
Obviously, there can be only one concurrent host-mode session per serial port.

Users make connections to your PC simply by dialing your modem's phone number
and then going into terminal emulation mode.


9. SUMMARY OF FILES

Filename are all relative to the Kermit 95 directory.

  HOST.CFG             The host-mode configuration file.
  K95D.CFG             The K95D.EXE configuration file.
  HOSTMODE.BAT         Starts the host-mode management program.
  K95D.EXE             Daemon for managing incoming Telnet connections.
  DOCS\HOSTMODE.DOC    This file.
  SCRIPTS\HOST.KSC     The host-mode script.
  SCRIPTS\HOSTTCP.KSC  Script to start host mode for TCP/IP users.
  SCRIPTS\HOSTMDM.KSC  Script to start host mode for dialup modem users.
  SCRIPTS\HOSTCOM.KSC  Script to start host mode for direct serial connection.
  SCRIPTS\HOSTMODE.KSC The host-mode management program.
  USERS\USERS.DAT      The user ID database.
  USERS\GREETING.TXT   Short greeting text for users when they log in.
  USERS\HOSTMODE.TXT   Help text displayed by "Help" menu item.
  USERS\MESSAGES.TXT   Messages from users to the proprietor.
  USERS\username.MSG   Message(s) to a particular user.
  INCOMING             Directory to which all users can upload files.
  PUBLIC               Directory from which all users can download files.
  PUBLIC\HOSTUSER.DOC  A user guide which users can type or download and read.

The HOST.CFG configuration file is shared by HOSTMODE.KSC, HOST.KSC, and all
the other scripts, so you only need to change configuration parameters in one
place.


10. IDEAS FOR IMPROVEMENT

Since Kermit 95's host mode is written entirely in the Kermit script language
and executed by Kermit itself, anybody can make improvements.  Here are a few
ideas:

 . Callback capability for extra security.  User logs in with valid password,
   callback number is looked up in the database (just add one more field),
   and the host script calls the user back before presenting the menu.

 . Ability of users to find out about other users, see who's logged in, etc.

 . More-style paging of typed files and directory listings.

 . Ability to send messages, as well as TYPE and DIRECTORY material, to the
   user's local printer.

 . File menus.

 . Better messaging features, interactive chat sessions, etc.

 . Limits on the length of sessions, the number of concurrent sessions, disk
   quotas, ANSI screen coloration, etc etc...  Hey, it's BBS!

Several programming considerations might not be totally obvious.  The worst
of them is the conflict between the use of the backslash (\) character by
Kermit's command scanner, and its use by Windows as a directory separator.
In the Kermit script language, backslash is used to introduce variables,
function calls, and numerical representations of special characters.
Variables, unless you take precautions to the contrary, are evaluated
recursively so, for example, if the variable \%f contains a Windows filename
such as C:\K95\OOFA.TXT, then any reference to this variable, such as:

  echo "\%f"

would result in its full evaluation, giving undesired results like:

  "C:K95OA.TXT"

Windows 95, at the API level, can accept forward slash (/) as well as
backslash (\) as a directory separator, and therefore so can self-contained
Kermit 95 commands such as SEND, MKDIR, etc, that take filenames or directory
names.  Unfortunately, however, Windows commands and programs such as DIR
will not accept forward slashes, and so before feeding a filename to one of
them, you'll need to do:

  \freplace(xxx,/,\\)

where xxx is the name of the variable that contains the filename.

On the other hand, if the directory name contains backslashes to begin with,
then any unguarded reference to it will result in the backslashes being
interpreted recursively by Kermit's command scanner.  To avoid this, use
constructions like:

  open read \fdefinition(_userfile)

\fdefinition means "return the definition of the macro" without evaluating
it further.  Similarly for \%x variables:

  open read \fcontents(\%f)

A related consideration to be aware of is that you can't start a DOS shell
and redirect its input and/or output to the communications channel.  It just
doesn't work, don't even try it.  If it did work, we could easily use (e.g.)
REDIRECT on COMMAND.COM to give hostmode users an interactive DOS session.
(REDIRECT presently works in only one direction, and then only through the
use of temporary files.)

(End)