ARP broadcasts - bridged wireless adapter - dup IP address

[Jallot]

Hello,

I've got a situation where a bridged wireless adapter, when responding to ARP broadcasts, is causing duplicate entries to be made for the same IP address. This causes havoc on the LAN such as out-of-order, retransmissions, and duplicate packets.

Here is my setup:

-VirtualBox (4.1.6 r74727)
-linux host (Ubuntu 10.04 LTS)
-guest OS (Windows XP SP2). Guest OS has guest additions installed
-Virtual Box guest networking settings : Bridged Adapter, Intel PRO/1000 MT Desktop (8254OEM), Promiscuous mode - Allow ALL, Cable Connected
-D-link Wireless N desktop PCI adapter model DWA-525

The IP address of the wireless adapter (d-link) on the host is 192.168.1.4 with a MAC address of 84:C9:B2:XX:XX:XX. The IP address of the same adapter when bridged for the guest OS is 192.168.1.54 with a MAC address of 08:00:27:XX:XX:XX.

When ARP broadcasts ask who has "192.168.1.54", there is a reply (verified using Wireshark) with MAC 08:00:27:XX:XX:XX as well as 84:C9:B2:XX:XX:XX. This causes a duplicate entry. The MAC 08:00:27:XX:XX:XX is associated with 192.168.1.4 not 192.168.1.54.

I am not sure why this is happening. I have even created address mapping in the ARP cache of the linux host in the hopes that this would help. It does not. I've also played with setting arp_filter=1, arp_ignore=1, arp_announce=2 on the wireless interface but it did not help.

I can successfully ping from the guest OS to the internet as well as to LAN elements, but TCP connections on the guest OS are wrought with out-of-order, retransmissions, and duplicate packets.

Can anyone help me?

thanks.

[vbox4me2]

Are you sure your local (real) router is not poising the arp table ?

[Jallot]

Are you sure your local (real) router is not poising the arp table ?

It's not the router. It's coming from the wireless adapter. Apart from the "who has 192.168.1.54" broadcasts, the wireless adapter itself is generating 2 Gratuitous ARP messages for 192.168.1.54, one for MAC 08:00:27:XX:XX:XX and one for MAC 84:C9:B2:XX:XX:XX. So even the adapter knows that a duplicate address situation exists.

[vbox4me2]

Could be 2 mac addresses from the same Bridge resulting in a 'dupe'. If you disable bridge or hostonly for the wireless adapter what happens then ?