virtualbox.org

Hello,

Deployment:
I am using GNS3 and VirtualBox. The topology is straightforward, Guest (Arch linux) connected to SW1 (Ethernet switch). Host (Windows 2008 Server) connected to SW1.

GUEST -> SW1 <- HOST

Guest network config:
Generic Driver
MAC: 08:00:27:FA:01:5F
IP: 1.1.1.4/24
Generic properties (added by GNS3):
dest=127.0.0.1
dport=10007
sport=20903

Host network config:
Host-Only
MAC: 08:00:27:00:14:FB
IP: 1.1.1.6/24

ping GUEST > HOST:
When I try to ping Host from Guest the packet capture shows the following ARP packets:
288 2369.570998000 08:00:27:fa:01:5f ff:ff:ff:ff:ff:ff ARP 60 Who has 1.1.1.6? Tell 1.1.1.4 (duplicate use of 1.1.1.4 detected!)
289 2369.572117000 ff:ff:27:fa:01:5f b0:b8:73:06:80:fa ARP 60 Who has 1.1.1.6? Tell 1.1.1.4 (duplicate use of 1.1.1.4 detected!)
290 2369.572439000 ff:ff:27:00:14:fb f0:a8:ad:05:80:fa ARP 42 1.1.1.6 is at 08:00:27:00:14:fb (duplicate use of 1.1.1.4 detected!)

The duplicate use of 1.1.1.4 should not occure since there are only to machines connected to the SW1 mentioned before. Now, the first packet is coming from the Guest. That one is correct. Now the second one is strange. I don't understand why the packet is being sent again but now with MAC address changed, note that the 08:00 is being change to FF:FF. Then I receive the reply from the Host also coming from FF:FF... address but announcing that 1.1.1.6 is on 08:00. I am confused. I would appreciate if someone could explain this behavior.

I should add that the ARP table on Guest (who initiates the communication) is not being updated after this ARP protocol communication.
However the Host will update its table with the entry:
1.1.1.4 08-00-27-fa-01-5f dynamic

On Guest the following PING output is showed:
From 1.1.1.4 icmp_seq=1 Destination Host Unrechable
From 1.1.1.4 icmp_seq=2 Destination Host Unrechable

ping HOST > GUEST:
The traffic is different when I try to ping from Host to Guest:
305 3192.763954000 ff:ff:27:00:14:fb 60:d4:9c:07:80:fa ARP 42 Who has 1.1.1.4? Tell 1.1.1.6
306 3193.585336000 ff:ff:27:00:14:fb 40:ee:62:07:80:fa ARP 42 Who has 1.1.1.4? Tell 1.1.1.6
307 3194.585615000 ff:ff:27:00:14:fb 90:3b:f7:07:80:fa ARP 42 Who has 1.1.1.4? Tell 1.1.1.6
308 3255.585463000 ff:ff:27:00:14:fb 70:66:0d:08:80:fa ARP 42 Who has 1.1.1.4? Tell 1.1.1.6

This one is even stranger. First of all the source FF:FF:... is not correct, it should be 08:00:... and the destination is even stranger bacause this packets should be FF:FF:FF:FF:FF:FF (broadcast). MAC addresses 60:d4:9c:... 40:ee:62:... 90:3b:f7:... seems to be randomly generated. Of course there is no ARP entry for 1.1.1.4 in Host ARP table and no ARP entry for 1.1.1.6 in Guest ARP table.

ping output on Host:
Pinging 1.1.1.4 with 32 bytes of data:
Reply from 1.1.1.6: Destination host unreachable.
Request timed out.
Request timed out.
Request timed out.

If someone faced similar issues and found any solution for that I will appreciate any suggestions.

I have opened this topic also on GNS3 forum: http://forum.gns3.net/topic6296.html

No need to post a link. We do not support GNS3 here.

Thank you for the fast reply.

I understand that this is not GNS3 forum however the case is that the generated packets are being sent with wrong MAC addresses. This addresses are not generated by GNS but they are preconfigured on VBox.

VirtualBox does not manipulate the MAC address it simply assigns one. If you are saying that the addresses are changing or they are being sent to the wrong one then you need to check the GNS3 program and see why.