Created attachment 147477 [details]
patch to create emulators/virtualbox-ose/files/patch-src-VBox-ExtPacks-VNC-VBoxVNC.cpp
Currently, VirtualBox always assigns port 5900 when listening for VNC connections via IPv6, as opposed to IPv4, where the port to use can be set using the property TCP/Ports.
The attached patch changes this behavior so that TCP/Ports also applies when listening via IPv6, thereby using the same port number for both IPv4 and IPv6.
It should be applied in /usr/ports and will create a file emulators/virtualbox-ose/files/patch-src-VBox-ExtPacks-VNC-VBoxVNC.cpp.