[Resolved] Host network drops after Virtual machine starts.

[rustemka71]

Hello!
OpenSuse 15.1 as Host
Windows 10 64bit as guest
VirtualBox and ExtensionPack version 6.0.14 r133895 (Qt5.9.7)

After guest starts ~ 5 seconds, host machine losts network - no pings to default gateway, but it can ping itself
After reboot host network is ok.

When I change network settings on Virtual machine to NAT -host network is alive

Do you have any idea?

[Martin]

Are you connected to a company network?
Then your switch port may be configured to just allow a single MAC address, ask your network administrator.

[rustemka71]

Thank You for answer!
Yes I connected to a company network. I asked network admin - switch allows 2 MAC addresses

[rustemka71]

When I start VM with NAT everything is ok.
And if I change to bridged network, i cant ping host from another computer. Network stops after this

2019-12-04T11:48:49.891533+03:00 kadrf3 kernel: [77948.627919] VBoxNetFlt: attached to 'eth0' / 78:ac:c0:c4:05:20
2019-12-04T11:48:49.905451+03:00 kadrf3 kernel: [77948.635278] device eth0 entered promiscuous mode

[Martin]

The network switch of your company disables your network port when it "sees" the virtual machine network address.
Your network administrator needs to look into it why.

[rustemka71]

Thank You very much! Our security admins blocks inregistered mac address.
Now problem is solved! You are my hero I spend a week with this problem

[socratis]

I spend a week with this problem

You could have simply asked 'Martin' for the solution...
Marking as [Resolved].