Virtualbox-ose 5.1.28: VNC / VRDP?


there are several hints in the www that under FreeBSD one at least can connect to a VM of Virtualbox via VNC. For example under

But using the --vnc option results in an error message "illegal option".

Otherwise a
VBoxHeadless -startvm "FreeBSD 10.1"
shows up:

Oracle VM VirtualBox Headless Interface 5.1.22
(C) 2008-2017 Oracle Corporation
All rights reserved.

30/10/2017 15:05:38 Listening for VNC connections on TCP port 40000
30/10/2017 15:05:38 Listening for VNC connections on TCP6 port 5900
VRDE server is listening on port 40000

But alle efforts connecting the local VRM are not successfull. By the way I wonder that VRDE und VNC server are listening to port 40000 at the same time.

So I wonder what is correct?
Does Virtualbox-ose-5.1.28 support VNC oder RDP or nothing?

My packages:
virtualbox-ose-5.1.28_2        General-purpose full virtualizer for x86 hardware
virtualbox-ose-additions-5.1.28 VirtualBox additions for FreeBSD guests
virtualbox-ose-kmod-5.1.22     VirtualBox kernel module for FreeBSD
Thanks and best regards
Please note that FreeBSD 10.1 has been EoL since December 2016 and is not supported anymore. Please upgrade to a supported version as soon as possible.

As for Virtualbox, the option is turned on by default:
VNC=on: Build with VNC support