RDP onto Virtualbox from s't. other than localhost. HOW???

[danast]

Summary:
VB 4.2 on Mac OS X 10.7.4 not allowing to get accessed via RDP outside localhost
Connecting to any virtual machine fails with "Connection refused" to any other arbitrary error message.

Outline:
So, today I spent a day on trying every imaginable way of getting Virtualbox to work as advertised with regard to running different OSs on a virtual machine and trying to access them remotely; but from something other than localhost; I can't see what use there would be to access a VM from localhost, but anyway, that's another story.

NONE worked outside localhost. Access was to be established from the same subnet. That's all.

At my disposal I had:
Windows7
WindowsXP
ClearOS
CentOS 6.x
Mac OS X

As clients for rdp access I tried:
CorD
Microsoft Remote Desktop
Apple RemoteDesktop
TSClientX

As authentication methods I followed instructions by Oracle (chapter 7.) for each of above configurations (if you understand stochastics in math, you'll get the picture of how many combinations there are available) with Guest access, external, NULL authentication and the new experimental SimpleAuth by Virtualbox. None worked from another than the localhost; SimpleAuth didn't work at all only once; NULL always worked for localhost; External worked once on XP (I know it's not supposed to work) but, again, only for localhost. Oh, and I forgot to mention, of course, I tried bridged, Natted, and a virtual host adaptor, with DHCP addressing on the VM as well as manual addressing.

What I mentioned was that when scanning my network using Apple Remote Desktop, I found that even though the IP addresses were advertised as Hostname --so domain name-- the actual IP ARA found was one entirely different, some whacky address from somewhere out of space and so not on any private subnet.

All of this was with VirtualBox 4.2.1 as well as Virtualbox 4.2.

Now, given some person at Oracle spent so much time on writing a manual on things that very obsiously do not work, writing here is my last little shred of hope that there is actually a way to get this to work that I missed, though from a rational point of view, that appears impossible to me right now.

Please, can someone help me?

[Y E T I]

Use Bridged mode and make sure a firewall is not blocking your guest. Use null until you get everything working properly.

[BillG]

The requirements for RDP are pretty simple. The target machine has to be reachable over a network. Unless you have some sort of routed network, that means all the machines being in the same IP subnet, as you have mentioned.

Start up a Windows guest in VirtualBox which is set to bridged mode. Check its network config to make sure that it is in the same IP subnet as the machines on the LAN. Make sure that remote desktop is enabled. (This should automatically enable the firewall port.)

From your machine on the LAN, check that you can see the Win 7 vm by name or by IP address. Start the Microsoft RDP client and try to connect to the vm's name or IP address. If it does not connect, post the IP config of each machine and the error message here.