






You can configure Telix to set up your computer as a remote host, so that
others may call your system and perform operations like transferring files and
chatting. It is like having a small BBS on your system. However, if your
security needs are complicated you should consider using a real BBS program. 

There are a few requirements to running Host Mode. Your modem must be able to
pick up the phone when it rings. The CD (Carrier Detect) Mask must be properly
defined in the Configuration Menu, so that Telix can tell when it is connected
to a caller. Telix must also be able to hang up the modem by dropping (turning
off) the DTR line on the RS-232 port. If one of these requirements is not met
you probably can not run Telix Host Mode on your system.














The Telix Host Mode is set in motion as a script in Telix's powerful SALT
script language. To run the Host Mode script, press Alt-G while in Terminal
mode, and then enter 'HOST' as the script file name. The script 'HOST' will
then be run. Several Host Mode configuration settings are kept in a file
called 'HOST.CNF'. The first time you run the Host Mode script, it will not
find this file, and automatically run the host Mode configuration script
'HCONFIG', which will create the file and allow you to change default values.
You should run HCONFIG when you need to configure the Host Mode. HCONFIG will
present you with the following parameters:













A:   Level One password. This is the password that callers must successfully
     enter to be admitted to the Host Mode and have Level One access.

B:   Level two password. This is the password that callers must successfully
     enter to be admitted to the Host Mode and have Level Two (Sysop) access.

C:   DOS shell password. This is the password that users of the Host Mode have
     to enter to use the Remote DOS Shell option.

D:   Shut down Host Mode password. This is the password that callers must
     enter to shut down the Host Mode, when they press Ctrl-Z.

E:   Host Download Directory. Level 1 access callers will only be able to
     download (have Telix send them) files that are in this directory. As
     well, the 'F'iles command will show them only the contents of this
     directory. 







                                 !! CAUTION !!

          DO NOT, UNDER ANY CIRCUMSTANCES, define this directory to
          the same name as the directory you run Telix in. If you
          did that, callers could download the Host Mode configura-
          tion file, which is stored there, and see your passwords. 

     Level 2 access callers may specify any download path, but this is the
     default.

F:   Host Upload Directory. Level 1 access callers will only be able to upload
     (send to Telix) files into this directory. Level 2 access callers can
     specify any path, but files will go here by default.

G:   Connection type. This can be either 'Modem' or 'Direct'. Use 'Modem' if
     your host system is being accessed through a modem, or 'Direct' if two
     computers are hard-wired. This stops Telix from trying to initialize a
     non-existent modem. or trying to determine the caller's baud.



There is one other important parameter which must be properly set for Host
Mode operation. This is the Auto Answer string, which is defined in the 'Modem
and dialing' page of the Configuration Menu. This string is sent to the modem
when Telix enters Host Mode, and should make the modem pick up the phone when
it rings. The default string is set up for Hayes compatible modems. It is:

                            'AT X1 S0=1|^M'       

where

AT        The modem attention code.

X1        Tells the modem to reply with extended result codes. This means the
          modem indicates the caller's baud rate.

S0=1      Tells the modem to answer after one ring.

^M        Sends the terminating Carriage Return character.

There are two optional text files which are displayed to callers if they
exist, called LOGO.MSG, and WELCOME.MSG. 






The Host Mode can actually be run once it's configured. Telix will make a note
in the Host Mode audit file HOST.LOG and then will immediately send the Host
Mode init string to the modem. Telix then waits for a caller. 

While in Host Mode, on the local side, the user can always press Esc to exit
Host Mode, or End to terminate the current caller. He can also enter commands
for the remote caller, so that a novice caller can be helped along by the host
operator. Also the current caller will be automatically terminated if there is
inactivity for five minutes, or the connection is lost. This is all noted in
the host audit file. 

If the caller has only access Level One, references to other disk directories
than the ones defined in HCONFIG are ignored.  All operations take place in
the defined directories. Telix protects your files from being accidentally
overwritten by the caller as well.





Telix knows a caller is online when the Carrier Detect signal turns on. At
this point, Telix will try to determine the caller's baud rate. Most Hayes
compatible modems can be initialized to send the string 'CONNECT baud' where
baud is the baud rate of the caller, when they sense a connection. If Telix
sees this string it will switch to the appropriate baud. If this string is not
received within a few seconds of the connection, Telix will leave the baud
rate at whatever it was. Also, it should be mentioned that Telix can not
determine the caller's other settings like parity, data bits, and stop bits.
These must already match Telix's settings.

If the file LOGO.MSG exists in the Telix directory it is displayed to the
caller. Basically, it should identify the system. Then Telix will ask the
caller for his/her name. The name must be at least five letters long and is
only used when indicating the caller in the Host Mode audit file. 

If a password has been defined Telix will ask the caller for it. The caller
has three tries to complete the password. All password attempts, successful or
failed, are written to the Host audit file. If the caller enters the Level One
access password, he may manipulate only the disk directories defined in
HCONFIG. Any other directories can not be accessed. If he enters the Level Two
access password, the caller may use full pathnames in all file specifications.
The level 2 password should only be kept for yourself or those you completely
trust, as a Level 2 caller can access any files on your system.



If there is a file called WELCOME.MSG in the Telix directory, it is shown to
the caller. This file can contain further identification or news that you only
want valid callers to see. After each 23 lines the caller is prompted to press
any key to continue. The caller may press Ctrl-S to pause at any time, and
Ctrl-C or Ctrl-K to abort the listing. After the TELIX.MSG file is displayed
the caller is presented with a menu of options:

          Ŀ
           Files  Type  Upload  Download  Shell  Chat  Goodbye ?  
          

The action to be taken is selected by entering its first letter. Case does not
matter. The host operator is free to enter any keystrokes for the caller.

The 'Files' option allows the caller to list the files in the current disk
directory. The caller must press a key after each screen. The output is not
echoed on the local screen. If the caller has access level two they are
prompted for a filespec, which may include the * and ? wildcard characters so
that the contents of other directories than the 'Host download dir' may be
listed.


The 'Type' option allows the caller to view any ASCII file in the Host
Download Directory, or in any directory for access Level 2 callers. The same
format and commands are available during this command as for the displaying of
the optional message file TELIX.MSG.

The 'Upload' option allows the caller to send a file to the host. The caller
is shown the following menu:

       Ŀ
        Modem7 SEAlink Xmodem 1k-Xmodem G-1k-Xmodem Ymodem Ymodem-g 
                             Which protocol?                        
       

The caller should select the appropriate protocol by its first letter (or 'E'
for Ymodem-g). The caller is also asked for the filename. The transfer is then
initiated. Level 1 callers may only upload files into the 'Host Upload
Directory' defined with HCONFIG.

The 'Download' command allows a caller to receive a file from the host. The
caller must select the protocol as described above, and then must tell Telix
the file(s) to send. The transfer is then initiated. Level 1 access callers
may only download files from the 'Host Download Directory' defined with
HCONFIG.



The 'Shell' command is very powerful.   It is also very dangerous command. It
allows the caller to run a DOS shell on your system, except that the caller
receives the output, and the caller enters the keystrokes. This command is
basically similar to entering 'CTTY COMx' at the DOS prompt. The remote side
has complete control of your system. 

                    !! This is obviously very dangerous !!

The caller can format disks, delete files, or perform any other operation. A
password must be entered to use the remote DOS shell to provide security. 

             !! BE VERY CAREFUL WHOM YOU GIVE THIS PASSWORD TO !!

They can do anything they want with your system. As well, don't leave it at
the default that Telix comes with. There are a few limitations in the remote
DOS shell. The caller will see program output only if the programs use
standard DOS output. Programs that write directly to the video screen will
work, but will not be seen by the remote caller. As well, programs that use
non-DOS methods of getting keystrokes will not receive the callers keystrokes.




Finally, under some systems, if the caller presses Backspace at the DOS prompt
when the current line is empty, DOS will hang on the Host machine. As these
are functions of DOS, there is nothing that can be done about these limita-
tions.

The 'Chat' command allows the caller to chat with the host operator. When the
caller presses 'C' the host operator is paged for 20 seconds. Press the Space
bar to chat with the caller, or any other key not to. Accepting the chat will
place you in Chat Mode, exactly as if you had used the Alt-Y command. The
caller's keystrokes are echoed back to him/her however, so that he/she can see
them.

Finally, the 'Goodbye' command allows the caller to log off the host. An entry
noting the time and date is made in the host audit file, and Telix then waits
for a new caller.

The caller may also use one other command that is not displayed in the menu.
This is to shut down the Host Mode. If the caller presses Ctrl-Z and success-
fully enters the shut down Host password defined in the Configuration Menu,
the Telix Host Mode is shut down and Telix returns to whatever it was doing
before Host Mode was initiated.
