[Solved] VirtualBox's in-built RDP server not accepting connections

[Esbeeb]

I'm running VirtualBox 6.0.10 on MX Linux 18.1
I've created a Windows 10 Home VM. It works fine. Note that Windows 10 Home does not include an RDP server itself, but Virtualbox has a built-in RDP server feature, where you connect to your localhost (the host, not the guest) on port 3389 (with, say, grdesktop, or remmina). But this feature doesn't work for me.

Here are my needs:
- Windows VM starts automatically at boot time.
- other MX linux users on that system should be able to RDP into the Windows VM (one at a time only, as in, whomever is physically sitting in the seat in front of the machine, from their Linux desktop)
- Ideal, but not essential: The ability to pause the VM when not in use. And an ability for any user, whether Sysadmin or not, to do that pausing/unpausing would be great.

For now, I'm starting the VM by right clicking it, then in the "Start" menu, I choose "Headless Start". It boots up, which I can see in the Preview box, and is shown as having a "Running" state. Remote Desktop Server Port is shown as 3389.

I've tried both grdesktop (0.23), and remmina (1.2.31.2), connecting to either "localhost", or my LAN IP address of the host (not guest). No combination can connect.

I know that port 3389 is listening on my localhost, when I use the command:
sudo nmap -p 3389 localhost

The port is shown as open.

tcpdump also shows a little traffic on port 3389 going back and forth when I try to connect. So something is happening there. The packets aren't just one-way. But there are no useful error messages anywhere to be seen. Not yielded by the VMs logs themselves, nor by Reminna, nor by grdesktop.

In my Windows 10 VM, in the Settings for that VM, in the Display-related settings, the "Enable Server" checkbox is indeed checked. I've left other settings there at the defaults (as in, port 3389, and the Authentication method is by default "Null"). Then in Remmina/grdesktop, I don't try supplying a username, password, or Domain.

Any suggestions?

[socratis]

First of all, a "philosophical" question that I have: why are you trying to connect via RDP to a VM that's running on your system? Or did I miss something?

Second, I have a Mint19 host and I have no problem using Remnina to connect to localhost:3389.

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

[mpack]

First of all, a "philosophical" question that I have: why are you trying to connect via RDP to a VM that's running on your system? Or did I miss something?

I've done that. No big mystery really: running headless can be less intrusive and less error prone than having one or more windows open (especially on Windows hosts where it hogs a taskbar slot). Then run RDP only when you actually need to see what the VM is doing. It can also bypass VirtualBox graphics issues if the guest has native support for RDP.

I also find RDP servers works more reliably than VNC, even for Linux guests. Plus RDP clients are available for Windows, Linux and Android. No doubt there's one for OS X too though I have no experience of it. Also I expect that running a VM as a service works better if you run headless and RDP in when you need to.

[Esbeeb]

Thanks for the reply!

First of all, a "philosophical" question that I have: why are you trying to connect via RDP to a VM that's running on your system? Or did I miss something?

I want other Linux users on the same Linux host system to all be able to share that one Windows 10 Home VM guest between each other, without any one Linux user stepping on the toes of any other Linux user, as they connect to, and disconnect from the Windows VM (which I'd like to run for weeks on end, only being powered down and back up by a Sysadmin, after performing any Windows Updates to the VM, which can greatly delay a Windows shutdown and startup, and users are lazy to properly wait for). Sometimes that Windows VM will go into a paused state, I'm hoping, automatically, as Linux users shut the lid on the laptop, and the laptop goes to sleep. Then the Windows VM would hopefully unpause again, when the laptop comes out of sleep.

Is there some other way you can recommend doing this sharing between Linux users, other than an RDP connection to VirtualBox's RDP service, for that VM?

I suppose the actual VM's folder on the host could be group-readable and writable by all the Linux users, and they could one at a time power it up and power it down, but I don't trust all my Linux users to perform that clean power-up and power-down of the VM every time, thusly leaving the VM in a clean, powered-down state for each other (and all lock-files on the VM are removed). All it takes is one lazy user to wreck it for the others, by not doing a clean powerdown, and just closing the lid on the laptop when he/she's done, before they stand up and leave for the day (that's what they are accustomed to being able to do on a normal Windows laptop whenever they want).

Second, I have a Mint19 host and I have no problem using Remnina to connect to localhost:3389.

Great to hear.

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

Attached.

[socratis]

00:00:00.055752 VirtualBox VM 6.0.10_Debian r132055 linux.amd64 (Jul 17 2019 19:08:41) release log

It looks like you're using the distro's fork version of VirtualBox. You can either ask in their forums/channels for help, or completely remove/uninstall/delete/purge their version and install the official version from the Linux Downloads section of VirtualBox. You can even add VirtualBox as a repository, so you could use your traditional install/upgrade/uninstall tools.

00:00:00.067041 Installed Extension Packs:
00:00:00.067082   VNC (Version: 6.0.10 r132055; VRDE Module: VBoxVNC)
00:00:00.067094   Oracle VM VirtualBox Extension Pack (Version: 6.0.10 r132072; VRDE Module: VBoxVRDP)

Careful there, you have both the official Oracle ExtPack as well as the VNC unsupported one. See ch. 9.22. Other Extension Packs of the User Manual for the special precautions that you have to take. Note that for the RDP server (VBoxVRDP) capability you only need the Oracle ExtPack.

Finally, I don't even see the VRDP server enabled! Are you sure you've enabled it in the VM Settings » Display » Remote Display?

As for your big project, I suggest we resolve the RDP issue in this thread and then you could open a new thread (with a matching title) where you describe what you want to do and how you envision this to happen.

[Esbeeb]

@socratis, your advice was fantastic.

In a nutshell, I re-installed Virtualbox6, but not from the MX Linux Testing Repos. i installed it in the way the official Virtualbox documentation said to do, but first I had to carefully back out of using the way MX Linux does it.
To see the gory details of that, see:
https://forum.mxlinux.org/viewtopic.php ... 54#p521454

Now Remmina can successfully connect to Virtualbox's RDP server, and I can see my Windows VM!!

[socratis]

Glad I could help. And thank you for marking the topic as [Solved]...