Connect VNC via SSH

#!/bin/bash

# this script connects via SSH to the destination host, starts an X11VNC server and connects to it
# it uses randomized IP addresses and ports so that the possibility of clashing with other listening programs is minimized
#
# To install the packages needed (e.g. in Ubuntu):
#  apt-get install x11vnc ssvnc

# bail if not enough options
if [ "$1" = "" ]; then
    echo "Usage: $0 hostname [vncviewer-options]"
    exit 1
fi


# range of usable ports
FLOOR=25900
RANGE=25999
LOCALPORT=0
while [ "$LOCALPORT" -le $FLOOR ]
do
  LOCALPORT=$RANDOM
  let "LOCALPORT %= $RANGE"
done

# set the same port for remote and local
REMOTEPORT=$LOCALPORT

RANGE=255
IPPART=$RANDOM
let "IPPART %= $RANGE"

# use a random localhost IP address so we don't accidentally conflict with anything
LOCALHOSTIP=127.59.$IPPART.1

# SSH to the 1st argument, start x11vnc there
ssh $1 -L $LOCALHOSTIP:$LOCALPORT:$LOCALHOSTIP:$REMOTEPORT -vvv -o ControlMaster=no "x11vnc -nopw -ncache -display :0 -listen $LOCALHOSTIP -noipv6 -norc -wireframe -rfbport $REMOTEPORT " &
SSHPID=$!
# ^ save SSH PID to kill the connection later

# don't use $1 anymore
shift
# wait for the connection to be established, just to be on the safe side
sleep 10
# launch the viewer
ssvnc -viewer -use64 -nocursorshape -nobell -encodings hextile -sendclipboard -scale 0.9 $* $LOCALHOSTIP::$LOCALPORT &
# alternately, use the
##vncviewer 127.59.0.1:$LOCALPORT

wait $!
# ^ wait for VNC to exit
# close the SSH tunnel
kill $SSHPID