Using Multiplicity 4 on an overlay network

from Stardock Forums

Hi everybody!

I'm totally new to Multiplicity and am testing the Pro version of Multiplicity 4 on two computers running Windows 11 23H2. I'm trying to get it working in KVM mode over my overlay network.

This means that my different computers are connected to several Wi-Fi and Ethernet networks, and these computers are all connected together by this overlay network, Nebula in this case. Each computer can directly reach any other computer using the overlay network subnet 10.55.555.0/24. This network has been assigned to the Private profile.

I've installed the Multiplicity 4 Pro trial on one computer, in primary mode, and on another computer in secondary mode. Both computers are at the same location and on the same network for this test. Both computers have a physical network adapter (Ethernet or Wi-Fi) and a tun network adapter for the overlay network. Multiplicity is showing only the IP address corresponding to the physical adapter in its UI.

Multiplicity is working perfectly over the "physical network", and I can get the display of the secondary computer shown on the primary, and can interact with it.

However I cannot find a way to get Multiplicity to communicate over the overlay network, which would be very useful to me for accessing computers at my other locations.

I took a Wireshark trace on the primary computer. When I try to add the secondary computer using its overlay network IP address, and press the Test button, there is not even a single packet sent by Multiplicity over the overlay network. And I'm getting the following error message: "Connection failed due to an unknown protocol error (3)."

I disabled the Windows firewalls on both computer and am getting the same error.

I would like to know if there is a possibility to tell Multiplicity 4 which network adapter, or subnet, it should use.

I thank you in advance for your advice.

multiplicity
3,069 views 7 replies
Reply #1 from Stardock Forums Top

Hello,

Hello,
Sorry to hear you are having issues. I have forwarded your problem/question to Stardock Support Team for their assistance. Please keep an eye on this thread for any updates. We appreciate your feedback and patience.

Thank you,

Basj,
Stardock Community Assistant

Reply #2 from Stardock Forums Top

Hello Basj,

I thank you very much for your answer.

I'll keep an eye on this thread.

Regards,

Jean-Christian

Sins of a Solar Empire II
Reply #3 from Stardock Forums Top

I am a bit out of my wheelhouse here but let me know what you think about this...

Since you seem comfortable with advanced networking, I have a few suggestions that might help you force communication over the overlay network:

1. Prioritize the Overlay Network in Windows

You can adjust the Windows routing table to ensure that communication with your overlay network subnet (10.55.555.0/24) is prioritized over the physical adapters. Here’s how:

  • Open an elevated Command Prompt (Run as Administrator) on both computers.
  • Add a route to ensure traffic for the overlay network subnet is sent via the overlay adapter. For example:
    route add 10.55.555.0 mask 255.255.255.0 <PrimaryComputerOverlayIP> metric 1

Replace <PrimaryComputerOverlayIP> with the Nebula overlay IP address of the tun adapter on the primary computer.

This ensures that traffic intended for the overlay network is routed through the correct adapter.

2. Lower the Network Adapter Metric for Nebula

To further ensure the overlay network takes precedence over physical adapters:

  1. Open Network Connections from the Control Panel (Control Panel > Network and Internet > Network Connections).
  2. Right-click the Nebula tun adapter and select Properties.
  3. Highlight Internet Protocol Version 4 (TCP/IPv4) and click Properties.
  4. In the advanced settings, uncheck "Automatic metric" and set the metric value to a lower number (e.g., 10).
  5. Restart the Multiplicity service (in the system tray) after making these changes.

This step will prioritize traffic through the overlay network.

3. Verify Ports on the Overlay Network

Multiplicity uses TCP/UDP Port 30564 by default for communication (list of all port). If Nebula has any firewall or routing rules, please ensure this port is open and allowed over the overlay network.

You can test the connection between the two computers by trying to reach the secondary computer's overlay network IP address using this port.

4. Confirm Virtual Adapter Recognition

After applying the steps above, restart the Multiplicity service (in the system tray) on both computers to ensure the software detects the updated adapter configuration. Once restarted, try connecting using the overlay network IP address.

Please let me know how this works for you or if you have any additional questions!

Sean Drohan
Stardock Product Lifecycle Manager

 

Reply #4 from Stardock Forums Top

Hi Sean,

I thank you very much for your very detailed answer.

I've followed the steps you mentioned.

At 1. I had to change the existing route, as Nebula creates routes for itself. Here are my routes after the change you suggested:

route print
===========================================================================
Interface List
 36...........................Nebula Tunnel
  6...54 ac 23 41 f0 0f ......Check Point Virtual Network Adapter For Endpoint VPN Client
 12...d4 f3 2d c4 a7 da ......Microsoft Wi-Fi Direct Virtual Adapter
 16...d6 f3 2d c4 a7 d9 ......Microsoft Wi-Fi Direct Virtual Adapter #2
 22...d4 f3 2d c4 a7 d9 ......Intel(R) Wi-Fi 6E AX211 160MHz
  1...........................Software Loopback Interface 1
===========================================================================

IPv4 Route Table
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0       10.12.14.1     10.12.14.233     30
       10.12.14.0    255.255.255.0         On-link      10.12.14.233    286
     10.12.14.233  255.255.255.255         On-link      10.12.14.233    286
     10.12.14.255  255.255.255.255         On-link      10.12.14.233    286
      10.55.555.0    255.255.255.0         On-link      10.55.555.15     11
     10.55.555.15  255.255.255.255         On-link      10.55.555.15    266
    10.55.555.255  255.255.255.255         On-link      10.55.555.15    266
        127.0.0.0        255.0.0.0         On-link         127.0.0.1    331
        127.0.0.1  255.255.255.255         On-link         127.0.0.1    331
  127.255.255.255  255.255.255.255         On-link         127.0.0.1    331
        224.0.0.0        240.0.0.0         On-link         127.0.0.1    331
        224.0.0.0        240.0.0.0         On-link      10.12.14.233    286
        224.0.0.0        240.0.0.0         On-link      10.22.222.15    266
  255.255.255.255  255.255.255.255         On-link         127.0.0.1    331
  255.255.255.255  255.255.255.255         On-link      10.12.14.233    286
  255.255.255.255  255.255.255.255         On-link      10.22.222.15    266
===========================================================================
Persistent Routes:
  None

IPv6 Route Table
===========================================================================
Active Routes:
 If Metric Network Destination      Gateway
  1    331 ::1/128                  On-link
  1    331 ff00::/8                 On-link
 36    261 ff00::/8                 On-link
===========================================================================
Persistent Routes:
  None

We can see that the metric is now 11.

I did 2. and set the Nebula adapter metric to 10.

I've authorized the Multiplicity inbound ports in the Nebula firewall on the secondary computer.
The Windows firewall are still disabled on both computers.


On my primary computer I can do a telnet on the port 30564 of the secondary computer over the Nebula overlay network and get
an answer, with seemingly random characters. I can see the connection being done in Wireshark.

I did 4.

However I've still the exact same problem: when I try to start the KVM connection over the Nebula overlay network, there is
no packet at all leaving the primary computer, when I look in Wireshark.

It looks to me like Multiplicity is not seeing the Nebula network adapter.

I have two other remote connection software which are working fine over Nebula.

Do you have another idea?

I thank you in advance.

Best regards,

Jean-Christian

Reply #5 from Stardock Forums Top

Check what port 30569 is doing, I think that's the kvm port.

Reply #6 from Stardock Forums Top

On the primary computer, I can telnet to the port 30569 of the secondary computer over the overly network and I get a connection.
I can see the packets exchange in Wireshark.

However, when I try to connect with Multiplicity, no packet is leaving the primary computer. Wireshark shows nothing...

Reply #7 from Stardock Forums Top

Note that I have the same issue on two computers: one is a laptop under Windows 11 and the other one is a VM running Windows 10.

In fact, I just did an additional test in Windows 10 and now it's working with the overlay network! Great! But I don't understand why it's still not good on the Windows 11. I'm going to check the whole configuration again.