Guest Bridged Networking Stops Working After Host Link Was Down

[ErikWlfn]

I tested bridged networking on a Windows 10 Host with a Windows 7 64-bit Guest and a Windows XP 32-bit Guest. They both exhibit the same problem with a bridged network adapter. If the host's bridged link was down when the virtual machine was started, or goes down temporarily after the virtual machine is started, communication is lost through the bridged adapter on the host. It is still possible to ping the host's address assigned to the real adapter, but no devices connected to the LAN on the real host adapter will communicate.

Virtual Network Adapter Windows 7 64-bit Intel PRO/1000 MT Windows XP 32-bit PCnet-FAST III

Host LAN Adapter Intel I219-V (1 Gb) VEN 0x8086 DEV 0x15B8 Host OS Windows 10 64-bit 10.0.19042

The work around for the problem is to temporarily disable and then enable the host LAN adapter using the Network Connections in the Control Panel. Then disable and enable the virtual network adapter in the devices menu for the virtual machine. After doing both of those things, the bridged adapter will communicate again. I have noticed that it sometimes recovers if I just temporarily disable the network adapter for the virtual machine, but that seems to depend on whether the host adapter was up when the virtual machine was started.

I noticed this problem on a LAN port connected to a test network that normally has the switch powered off until I need to run tests. If I power up the switch after starting the virtual machine then there is no communication to the network switch until I perform the steps that I outlined.