Problem with VNC 4.0 & putty (ssh tunneling)

[Michael Russell]

Greetings,
   I am using VNC 4.0 Server & Client (build of Jun 15, 2004).  My setup is
as follows:
   VNC Server machine:
     VNC Server 4.0
     putty 0.56
     in Command Prompt Window:
        putty -N -R 5900:localhost:5900 -l vncfwd mail.mathtech.com
        (putty pops up window where I enter password for 'vncfwd' account).
   VNC Client machine:
     VNC Client 4.0
     I enter 'mail.mathtech.com' and click "OK"
     I get connected for a flash (less than a second) and then disconnected.
   Passthru machine doing the tunneling is running Fedora Core 2.

   If I then look on the Server machine, I see a dialog box with:
     PuTTY Fatal Error
       Server sent disconnect message
       type 2 (SSH_DISCONNECT_PROTOCOL_ERROR):
       "Corrupted MAC on input."

   Note the following:
     1) If I use the VNC 3.3.7 client connecting to the 4.0 server, I do not
        have this problem.
     2) I tried this on another machine, which at first had the same problem.
        I installed cygwin ssh on that machine and used their ssh (instead
        of putty) and that worked fine.  When I went back to putty on this
        second machine, it also worked fine.  Quite puzzling.

   Thanks for any advice.


-- 
                                         Michael Russell
                                         russell "at" mathtech.com