
  Hello,

  This is an adaptation of a c_filter found in my archive. I don't know the 
  author but I hope he will accept my modifications in his code.

  The code has been modified to be a Windows DLL. It works with both Windows
  and DOS (from 700b37).

  It accepts standard passwords (like NetRom), MD2 password and the exact 
  password string (in case of secure transmission). The understanding of the
  password is automatic.

  73s from F6FBB.


  An example of CON_FILT.PSW file :

#
# exclamation mark needed (for c_filter BBS exchange)
#
!F6FBB-1>
#
# Open mode and only MD2 string
#
0 0
#
# List of passwords
#
F6FBB 1 password_of_f6fbb
F5CDC 1 password_of_f5cdc
F5NUF 1 password_of_f5nuf
#



   This is an adaptation of the original help text found in the file :

   This server use the CON_FILT.PSW file, that have this format:
   Every empty line, or line that start with the '#' are ignored.

   The first valid line are password request prompt.

   The second line is the filter mode :
      0 for OPEN SYTEM, 
      1 for CLOSED SYSTEM,
      2 for READONLY.
   An optional second number is 0 : only MD2, 1 : 5 numbers + MD2.

   The others line are the callsign, without ssid, flag and its password, like:
   CALL FLAG PASSWORD
   CALL FLAG PASSWORD
   ... etc.

   NOTE: PASSWORD is not needed if FLAG=0


   OPEN SYSTEM MODE
   If the call is not declared in the con_filt.psw file, the user will be
   connected without password request, userful for bbs forward, or user that
   do not want password.
   If a callsign is declared:
   if FLAG=0, the callsign is excluded, disconneted.
   if FLAG=1, the callsign is connected after the password request.

   CLOSE SYSTEM MODE
   Only the callsign declared in the con_filt.psw may access to the system,
   the other will be disconneted.
   For declared callsign:
   if FLAG=0, the connection is accepted without password request.
   if FLAG=1, the connection is accepted, but the password will be requested.

   READONLY MODE
   Only the callsign declared in the con_filt.psw may have access to the system,
   the other will only have read-only access.
   For declared callsign:
   if FLAG=0, the connection is accepted without password request.
   if FLAG=1, the connection is accepted, but the password will be requested.

   >  Prompt must be long at most 80 characters
   >  Password my be long at most 255 characters, without space.
   >  This program, if renamed C_FILTER.EXE, run also under FBB 5.15a and upper

   The server use a temporary file XXXXXX.CFT, where XXXXXX is the callsign of
   the user, to store the calculated password and date time of any unsuccesful
   logon; you do not need to touch this file, all management will be done by
   con_filt; the temporary file will be automatically deleted when not more
   needed.

   The server use both the standard 5 letters password and the MD2 (c)RSA
   alghoritm. The user may answer the exact password, in standard or md2 mode, 
   the server will decode automatically the corrected mode.

   Be sure that uppercase and lowercase match. The system is case-dependant.
