2020-04-16

Notes on setting up a reverse ssh tunnel.
Starting with understanding how it is done on Dazzle via PiTun.


system_defaults.py defines ports from 028 .. 214
    sshports['xxx']['kahe']             = 136      #  Kahe, in-office test machine
    monitor_base = 10100
    tunnel_base = 20100
    pi_server='128.171.154.46' #ulili.soest.hawaii.edu

It is safe to set up a tunnel port in the 400-600 range.


####  check_tunnel.bash
    MONITOR_PORT="10400"
    DEFAULT_PORT="20400"
    PORTAL="128.171.154.46"
    COMMAND="autossh -M$MONITOR_PORT -f -N -o \"StrictHostKeyChecking=no\" -o \"ServerAliveInterval 60\" -o \"ServerAliveCountMax 3\" -R $PORT_VALUE:localhost:22 autossh@$PORTAL"
####  end check_tunnel.bash

Let's try to set this up on Morgana:


See /home/toby/bin/tunnel_dazzle

then, from elsewhere, 
    ssh -p 20400 toby@128.171.154.46

next, screenshare
    ssh -p 20400  -L 5901:localhost:5900  toby@128.171.154.46
    # It looks like screen sharing is not enabled on Morgana.



rigel02:PY3(~)$     ps aux | grep vino
    adcp      1169  0.5  0.5 672512 41512 ?        SLl  Apr02 123:35 /usr/lib/vino/vino-server
    # It looks like we need to have vino running


toby@morgana:~$     su -
root@morgana:~#     apt-get update
root@morgana:~#     apt-get install vino
    <snip>
    Setting up vino (3.22.0-1) ...
    Processing triggers for desktop-file-utils (0.23-1) ...
    Processing triggers for libglib2.0-0:i386 (2.50.3-2+deb9u2) ...
root@morgana:~#     ps aux | grep vino
    # nothing

    # Restart
toby@morgana:~#     ps aux | grep vino
    # nothing
   
toby@morgana:~$     sudo /usr/lib/vino/vino-server
[sudo] password for toby: 
16/04/2020 11:10:07 PM Autoprobing TCP port in (all) network interface
16/04/2020 11:10:07 PM Listening IPv6://[::]:5900
16/04/2020 11:10:07 PM Listening IPv4://0.0.0.0:5900
16/04/2020 11:10:07 PM Autoprobing selected port 5900
16/04/2020 11:10:07 PM Advertising security type: 'TLS' (18)
16/04/2020 11:10:07 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface
16/04/2020 11:10:07 PM Listening IPv6://[::]:5900
16/04/2020 11:10:07 PM Listening IPv4://0.0.0.0:5900
16/04/2020 11:10:07 PM Clearing securityTypes
16/04/2020 11:10:07 PM Advertising security type: 'TLS' (18)
16/04/2020 11:10:07 PM Clearing securityTypes
16/04/2020 11:10:07 PM Advertising security type: 'TLS' (18)
16/04/2020 11:10:07 PM Advertising authentication type: 'No Authentication' (1)
16/04/2020 11:10:08 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface
16/04/2020 11:10:08 PM Listening IPv6://[::]:5900
16/04/2020 11:10:08 PM Listening IPv4://0.0.0.0:5900


toby@morgana:~$     ps aux | grep vino
    root      1201  0.4  0.1   6728  3916 pts/0    S+   23:09   0:00 sudo /usr/lib/vino/vino-server
    root      1202  5.8  1.1  78144 23704 pts/0    Sl+  23:10   0:01 /usr/lib/vino/vino-server


toby@morgana:~$     /home/toby/bin/tunnel_dazzle
    ssh   -R 20400:localhost:22 dummy@128.171.154.46
    dummy@128.171.154.46's password: 

dazzle8:(~)$     netstat -lunt | grep 20400
    tcp        0      0 0.0.0.0:20400           0.0.0.0:*               LISTEN 


mulili:~ toby999$     ssh -p 20400  -L 5901:localhost:5900  toby@128.171.154.46
    toby@128.171.154.46's password:


On Mulili browse to: vnc://localhost:5901
    Connection failed to "localhost".
    The software on the remote computer appears to be 
    incompatible with this version of Screen Sharing.

    On Morgana:
    16/04/2020 11:22:05 PM [IPv6] Got connection from client localhost
    16/04/2020 11:22:05 PM   other clients:
    16/04/2020 11:22:05 PM Client Protocol Version 3.3
    16/04/2020 11:22:05 PM rfbClientConnFailed("No security type suitable for RFB 3.3 supported")
    16/04/2020 11:22:05 PM Client localhost gone
    16/04/2020 11:22:05 PM Statistics:
    16/04/2020 11:22:05 PM   framebuffer updates 0, rectangles 0, bytes 0