Ticket #3768 (new defect)
Starting from VirtualBox 2.1, packets are duplicated when written to a TAP interface
|Reported by:||fvichot||Owned by:|
I think the title says it all. After using VBox 2.0 for a long time, I switched to 2.2, and noticed all packets sent to a Tap interface (created using "tunctl") from the virtualized OS were duplicated. Ping would report "DUP!" packets, and this is confirmed by Wireshark for all protocols. I went back to VBox 2.1, and the problem is there too. VBox 2.0 works normaly.
To reproduce, it's quite simple: using latest VBox, configure a VM to boot using a tap interface (create it using "sudo tunctl") as network interface by selecting the Tap in "Network Configuration" -> "Access By Bridge" -> and select "tap0". Then start tcpdump or Wireshark on tap0, and then boot the VM. As soon as the VM is going to emits packets (for DHCP requests, for ARP, broadcast etc...) you will notice that all packets are duplicated. Try again with VBox 2.0, no such problem.
As always, if more info is needed, I would be happy to provide it. I would really like this bug fixed, it's quite a blocker for some software I'm working on...