Using an OS X virtual interface for guest machines

[TVick]

I'm running VirtualBox 5.0.14 on OS X 10.11.3 with a guest machine running Windows Server 2008 R2 Enterprise. I have a virtual adapter configured in OS X and I would like the guest machine to be placed in the same subnet as this virtual adapter.

In the VirtualBox networking settings for the VM, the adapter is set to Bridged and the VLAN appears in the list of available interfaces (as "vlan0") to which I can attach the guest. If I select the VLAN, however, the machine cannot communicate. Even with the host.

I'm wondering if this is a supported setup or if I am configuring something incorrectly. Can anybody here tell me if this is a supported setup in VBox 5?

[TVick]

I did some more digging and came up with more details.

The guest CAN communicate with the host (via PING) and the host can ping the VM. The host can ping the gateway but the guest cannot. Windows returns a "Destination host unreachable" error.

The guest machine MAC address is 08:00:27:C1:16:EC but this shows up in the routing table separated by periods rather than colons at address 10.14.2.15. Issue?

Code: Select all

Routing tables

Internet:
Destination        Gateway            Flags        Refs      Use   Netif Expire
default            10.33.1.254        UGSc            4        0     en0
default            10.14.2.254        UGScI           0        0   vlan0
10.14.2/24         link#10            UCS             1        0   vlan0
10.14.2.15         8.0.27.c1.16.ec    UHLWI           0        2   vlan0    499
10.14.2.201/32     link#10            UCS             1        0   vlan0
10.14.2.254/32     link#10            UCS             1        0   vlan0
10.14.2.254        link#10            UHLWIir         1        0   vlan0
10.33.1/24         link#4             UCS             6        0     en0
10.33.1.10         8:0:27:5d:ac:e4    UHLWIi          1       14     en0    970
10.33.1.15/32      link#4             UCS             0        0     en0
10.33.1.62         0:90:a9:d2:ce:6a   UHLWI           0        0     en0   1048
10.33.1.71         8:0:27:36:34:d0    UHLWI           0        6     en0    494
10.33.1.74         8:0:27:fb:af:57    UHLWI           0      196     en0   1025
10.33.1.76         8:0:27:3b:1f:5d    UHLWIi          1        4     en0   1080
10.33.1.254/32     link#4             UCS             1        0     en0
10.33.1.254        20:bb:c0:7d:ed:1b  UHLWIir         5        0     en0   1198
127                127.0.0.1          UCS             0        0     lo0
127.0.0.1          127.0.0.1          UH              1     1054     lo0
169.254            link#4             UCS             0        0     en0
169.254            link#10            UCSI            0        0   vlan0
255.255.255.255/32 link#4             UCS             0        0     en0
255.255.255.255/32 link#10            UCSI            0        0   vlan0

Further down the line, the switch the host is connected to shows the guest MAC address so it is clearly getting beyond the host machine but is stuck somewhere.

[socratis]

Don't you think it would serve you better if you actually shared the details of your setup? Full details I mean, not just "a bridged", "a vlan" and so on...

[TVick]

I thought most of the details in the first two posts were relevant to understanding the setup.

• OS X 10.11.3 host running VirtualBox 5.0.14
• Windows Server 2008 R2 Enterprise guest
• Host has a virtual interface called vlan0
• Guest network adapter is in bridged mode and assigned to vlan0
• With this network configuration, the guest machine cannot pass traffic beyond the host machine
• Routing table on host machine might be incorrect and the guest machine MAC address looks different
• Is this a supported setup?

What other information is necessary to do further troubleshooting?

[socratis]

• Host has a virtual interface called vlan0
• Guest network adapter is in bridged mode and assigned to vlan0

What other information is necessary to do further troubleshooting?

I thought I asked too about specific information, not "a vlan". The above two need clarification. What is the vlan0?

[TVick]

vlan0 is the system named assigned to the virtual interface on the host.

In the OS X System Presences, the host has a virtual interface called VLAN152 in which the OS assigned as vlan0.

Host system preferences

SystemPrefs.png (75.69 KiB) Viewed 5415 times

vlan0

VLAN.png (15.4 KiB) Viewed 5415 times

Then in VirtualBox, in the VM network settings, vlan0 is the selected interface for the bridged adapter.

VM Network Config

NetworkConfig.png (72.5 KiB) Viewed 5415 times

In the VM, when I configure the network adapter, I assign it a static address of 10.14.2.15. With this configuration I cannot ping anything other than the host and the VM.

I'd like to know if this is even a supported setup to use a virtual adapter for a guest machine. And if there is a reason the MAC address for the host appears separated by periods rather than colons in the host OS routing table. I think this might be the reason the traffic will not pass but I cannot determine if this is a Mac OS issue or a VirtualBox issue.

[socratis]

OK, I'll need to hit the books, since I haven't seen or used the vlan option in OSX. Be right back...
(figuratively )

[BillG]

I don't own a Mac, but in general you can only bridge to a physical NIC. Bridged networking inserts a filter driver which works with the device driver for the NIC to allow the host and guest to share the device. Virtual interfaces usually do not have the necessary software to handle this. I guess it all depends on how the virtual interface is implemented.

My guess is that if it didn't "just work", it isn't going to, no matter how you try to fiddle with it.

[TVick]

Based on what I'm seeing here it looks like it might be an OS X issue that is keeping the setup from working. I added a thunderbolt adapter to the host and put it in the same subnet and the VM works fine with that. It looks like it might be something with the way OS X tags the traffic on the virtual interface and the connection just can't be made. Since the virtual adapter is just a layer on top of the physical NIC, it seems that this setup will not work.

It's interesting that the adapter shows up in the list of options though. If anyone else has input I'd love to hear it.

[MikeJ72]

Hi TVick,

seems I‘m hitting the same Rock.
Did you manage to get your VLAN working on your Mac ?