FYI: to test, you need to have a network that supports jumbo frames, then snip the 2 wires on your patch cable (so 1gbps can't be negotiated), or set the VM to only negotiate 100mbps in the VM definition, but leave NetworkManager's automatic MTU detection enabled.
FYI: to test, you need to have a network that supports jumbo frames, then snip the 2 wires on your patch cable (so 1gbps can't be negotiated), or set the VM to only negotiate 100mbps in the VM definition, but leave NetworkManager's automatic MTU detection enabled.