network: bridged adapter (br0)

[Niki Waibel]

i see strange behavior when using the vbox briged network adapter connected to a linux bridge interface (ie br0):

all works very well with br0 (brctl addbr br0; ifconfig br0 <some_ip>). vbox guest can talk to the linux host, vice versa.

issue appears, as soon as some interface is added to the brige (brctl addif br0 eth0). the network connection between the host and the guest does not work anymore (ping fails, telnet can't reach any port anymore).

if you save the machine state and start the guest afterwards, network starts working as expected (guest can talk to host, vice versa).

pausing/resuming the guest does not change the infunctional behavior.

[Niki Waibel]

same for 3.0.4

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.