'Bridged Networking' on host vlan interfaces does not work

[nocternal]

I have searched the forums, and looked on the internet... and this seems to be a regression in the 4.2.0 release. Downgrading back to 4.1.22 on the same kernel resolves the issue.

I am on gentoo 64-bit, running gentoo-sources-3.6.0. Same results on 3.5.4

I have a vm-host with several 1q vlan interfaces on it. I then bind my VM's to a particular interface using the 'Bridge Adapter'. The VM's are vlan-agnostic.

The symptom I have on VB 4.2.0 is that none of my VM's have network access. As soon as I switch to NAT on the VM's everything works fine. Downgrading to 4.1.22 on the same kernel restores network access for the 'Bridge Adapter'.

daffy TAZ6 # cat /proc/net/vlan/config
VLAN Dev name    | VLAN ID
Name-Type: VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD
eth0.10        | 10  | eth0
eth0.11        | 11  | eth0
eth0.12        | 12  | eth0
eth0.13        | 13  | eth0
eth0.14        | 14  | eth0
eth0.20        | 20  | eth0
eth0.25        | 25  | eth0

My VM-HOST network layout:

[ROUTER]====1Q-TRUNK===[VM HOST]
                              eth0.10--bridged--VM1, VM2, VM3....
                              eth0.11--bridged--VM6, VM7, VM8
                              eth0.12--bridged--VM4
                              eth0.13
                              eth0.14--bridged--VM5
                              eth0.20
                              eth0.25

The ROUTER and VM-HOST have the VM's MAC address in their arp tables. The VM itself only has the VM-HOST's MAC address - but not the ROUTER's. The VM can communicate with the VM-HOST but not anything else on the same L2 vlan. All other devices on the same L2 vlan have VM's MAC address (after a ping, say) but the VM never has any of the other hosts in it's arp table. Seems like packets destined to the VM never make it past the VM-HOST. I don't see any odd kernel events.

This is the forum post I started prior to this bug - ​https://forums.virtualbox.org/viewtopic.php?f=7&t=51886

I can attach all the details here if need be.

[nocternal]

VM running on VB 4.2.0 with no network access.

[nocternal]

Tried an upgrade - still seeing the same problem on VB 4.2.2. Back to 4.1.22 for the time being...

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.

[mpounsett]

I'm seeing this behaviour in 5.2.12 on MacOS.

The host (MacOS) main ethernet interface is a .1 trunk.. there are several VLAN interfaces. In my VM's network properties I set up Bridged Adapter and set the Name to the VLAN interface I want it to have access to (vlan0).

With the guest (Debian 9) network configured, it is able to ping the host interface, but not the router on that VLAN.

If I switch the guest network properties back to NAT and reconfigure it with DHCP everything works fine.

host:

% ifconfig vlan0
vlan0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
	options=3<RXCSUM,TXCSUM>
	ether 2c:4d:54:99:e5:f5
	inet6 fe80::144d:7ee4:927f:b442%vlan0 prefixlen 64 secured scopeid 0xc
	inet 216.235.10.40 netmask 0xfffffff0 broadcast 216.235.10.47
	nd6 options=201<PERFORMNUD,DAD>
	vlan: 69 parent interface: en0
	media: autoselect (1000baseT <full-duplex,flow-control>)
	status: active

% netstat -rn | grep default
default            216.235.10.33      UGSc          126     1574   vlan0
default                                 fe80::%utun0                    UGcI          utun0

guest:

% ip addr list enp0s3
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:15:4f:c5 brd ff:ff:ff:ff:ff:ff
    inet 216.235.10.37/28 brd 216.235.10.47 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe15:4fc5/64 scope link
       valid_lft forever preferred_lft forever

% ip route show
default via 216.235.10.33 dev enp0s3 onlink
216.235.10.32/28 dev enp0s3 proto kernel scope link src 216.235.10.37