Use vncviewer to connect to remove VNC instances, such as KVM console.

vncviewer host::port
vncviewer calcium::5900

VNC Listener

This makes VNC listen for inbound client requests, like a callback.

vncviewer SecurityTypes=none -listen

A remote client sould then connect to you, port 5500

x11vnc Server

x11vnc -nopw -forever -loop500

vncviewer exo handler

    set -o xtrace
    host=$(echo "$1"|perl -ne '/vnc:\/\/(.+)[:\/]/ && print $1')
    port=$(echo "$1"|perl -ne '/:(\d+)$/ && print $1')
    echo "vncviewer $host::$port"
    vncviewer --geometry 1280x1024+2000+20 $host::$port
) >> /tmp/exo.log 2>&1