Linux virtual NIC adapter types "macvlan" or "macvtap" need Guest Addition Drivers?

[jmar83_the2nd]

Does somebody knows that? I have some problems on my VMs with, i can't ping/reach any virtual adapter IP (on Linux guests) from remote. Maybe the problem is that my linux guests don't have the guest additions drivers installed..?

I use them in bridge mode and access from an external client (remote) does not work. Also "ping" does not work from remote client.

• https://backreference.org/2014/03/20/so ... anmacvtap/
• https://developers.redhat.com/blog/2018 ... etworking/

Maybe it is a bug (it works without any problems on a physical (non-virtual) computer with freshly installed Debian 9.11. But not on VirtualBox (i use 6.0.10) with also a freshly installed Debian 9.11... so the problem must be somewhere on VirtualBox. Where can i submit a VirtualBox bug? (Will try it with guest addition drivers first, but i don't think that will solve my problem??)

Thank you very much for your feedbacks. :-)

[socratis]

To answer your original question, the GAs have no network drivers. Even if you use the virio-net option, you have to provide the drivers for your specific guest. For the majority of the OSes out there, the selected option in the template defaults is enough, the templates are carefully chosen so that the guest OS has built-in support for the NIC.

Now, your NICs (macvlan and macvtap) are virtual adapters AFAICS. Not sure why it would be a VirtualBox problem, given the fact that you've given 0 (zero) details about your setup and what you're trying to achieve. With real, actual numbers. "Ping doesn't work" can be due to a gazillion of factors.


PS. It works best if you first consolidate your posts and then sum them up in a coherent post, instead of splitting them up in 4 posts...

[jmar83_the2nd]

Thank you for your feedback.

It is 100% a virtualbox problem:

- On a freshly installed Debian 9 VirtualBox VM, the virtual adapters (macvlan, macvtap) don't work. With 'don't work', i mean ping and / or access (e.g. port 80) from a remote client
- On a freshly installed Debian 9 on a physical machine, the virtual adapters (macvlan, macvtap) work. Their IPs are reachable (ping and/or port 80) from a remote client


...so it's CLEARLY a VirtualBox problem and very easy to reproduce for the developers. (if they will fix it ever... i think i need a workaround, can't wait for months or years until the problem is solved :wink: )

Kernels from the Debian 9 System don't matter - "original" kernel vs. kernel from stretch-backports makes no difference.

4 posts? I only made another one regarding to that topic -> viewtopic.php?f=6&t=94776

The 3 other ones from the last time are also network-related, but not related to this virtual-adapter/network problem.

[socratis]

It is 100% a virtualbox problem:

As I mentioned:

you've given 0 (zero) details about your setup and what you're trying to achieve. With real, actual numbers. "Ping doesn't work" can be due to a gazillion of factors.

4 posts? I only made another one regarding to that topic -> viewtopic.php?f=6&t=94776

I didn't say "threads", I said "posts". You had 4 posts here and another 4 posts in the other (now locked) thread. You were practically replying to yourself, or thinking out loud.

I wonder if I should consolidate the two of them...

[jmar83_the2nd]

Oh, now i understand...

My VirtualBox setup:

• VirtualBox 6.0.10 on workplace, 6.0.12 at home - makes no differences on behavior, same problem on both versions
• VirtualBox Extension pack was installed
• NO guest additions drivers on guest installed
• VM Host (NOT guest) system is windows 10 pro x64 with current (2019-09-18) updates installed
• What i'm trying to reach ist just a 2nd ip so we can run different web services on different IPs (we don't use dns and can't use it due to technical reasons - so we need 2 IPs - 1 for apache, 1 for habridge (philips hue emulation for amazon alexa/echo... alexa newly (also gen. 2 devices) only work with port 80 since last updates - before last alexa update, e.g. port 81 was also usable for it.)
• VM has partially default settings for Debian x64 systems, BUT NOT for that options: USB (turned off), Audio (turned off), NIC (changed from Intel Desktop Gigabit 1000MT adapter to paravirtualized/VirtIO), Graphic Card RAM was set to 44MB - but all there thing should also not be relavant: First i was thinking the NIC may be relevant for that behavior, but it's not... same problems with AMD, Intel and paravirtualization/virtIO NIC(s)..
• The hardware platform where VirtualBox runs should not be relevant: Also same behavior on many different hardware platforms/computers/laptops!!

...but what's i trying to reach in not really relevant, and i've found another solution: add a 2nd VirtualBox NIC for the guest to get a 2nd IP - that's simple i would say. But: mavclan or macvtap would be nicer, because it would be equivalent to the Raspbian version of your software.

If you need more details, don't hesitate to ask me.

[fth0]

The hardware platform where VirtualBox runs should not be relevant

On the contrary, it could be very important:

Using the VirtualBox bridged networking mode, a net filter driver intercepts/injects network traffic from/to the physical network adapter on the host. First, this is done differently for wired and wireless adapters. Additionally, the net filter driver must somehow decide which network traffic it intercepts. While it knows the MAC addresses of the VirtualBox virtual network adapters from the VM configuration, it doesn't know the MAC addresses of the Linux macvlan/macvtap interfaces, at least not beforehand. Depending on the combination of the type of the physical network adapter and the implementation of the net filter driver (which I don't know in detail), I can imagine different possible obstacles.

@jmar83_the2nd:
What types of physical network adapters did you try?

@socratis (and the other VirtualBox network expert users):
What do you know about how the net filter driver chooses which network packets to intercept? Or does it duplicate the whole network traffic when intercepting?

[jmar83_the2nd]

"What types of physical network adapters did you try?"

All...

[Martin]

According to chapter 6.5 in the manual

Some adapters strip VLAN tags in hardware. This does not allow you to use VLAN trunking between VM and the external network with pre-2.6.27 Linux kernels, or with host operating systems other than Linux.

[jmar83_the2nd]

Why that issue will not be fixed for Windows Host systems? Is that not possible, because it's "by design"..?

But what i do is NOT VLAN trunking (with VLAN ids/tags) - not really in my opinion. It's name ist just "macvlan" - which is confusing...

So i don't have differnt VLANs. (?)

"macvtap" also has the same problem!

???

[socratis]

Jan,
I consolidated 7 (SEVEN) of your messages.

Please try to keep your thoughts coherent and consolidate them in 1 post, don't post 3, 4 or more posts with a single line. This is not IRC, it's a forum, and it makes the discussion difficult to follow. Thanks...

Plus it makes my e-mail client go "bing" all the time, and I have a sensitive hearing...

[jmar83_the2nd]

I'm sorry, that working stress makes me thoughtlessly sometimes...

[fth0]

"What types of physical network adapters did you try?"

All...

This doesn't answer my question ... perhaps you didn't understand the question?

But what i do is NOT VLAN trunking (with VLAN ids/tags) - not really in my opinion. It's name ist just "macvlan" - which is confusing...

So i don't have differnt VLANs. (?)

Correct. The name macvlan should convey the idea that you have virtual ethernet connections by just using multiple MAC addresses for the same Ethernet interface. There are no VLAN tags involved.

[Martin]

Did you change the "Promisc Mode" setting for the virtual network adapter from the default "deny" to allow multiple MAC addresses?

[jmar83_the2nd]

"This doesn't answer my question ... perhaps you didn't understand the question?"

Oh, you meant the "real" physical adapters - not the adapters they are "physical" for the vm.

The "real" physical adapters was from Realtek and Intel and "Promisc Mode" was also not solving the problem, when i remember right..

But i've set the "physical" lan adapter of the debian VM (which is not really physical) to promisc mode enabled. I read that in different manuals, that the physical adpter (where the macvlan adapter is set up as a bridge) must have promisc mode enabled.

[Martin]

I meant the checkbox in the advanced network settings of the virtual network adapter in the Virtualbox guest / VM configuration.
(or the corresponding VBoxManage parameter )