Internal network problem

[yogesh.mundada]

Hi,

I want to create following topology.

node2
|
node0 ---- node1
|
node3

I want that node2 and node3 should transfer messages through node0. So I decided to put node0,node2 on internal network n0n2 and node0,node3 on internal network n0n3.
I bridged two interfaces on node0 (one connecting to node2 and other to node3) under a software bridge br0.
Now when I ping from node2 to node3, ping works fine. But if I run tcpdump on br0 at node0, I do not see any ICMP echo requests and replies.

Here is the relevant output of showvminfo for node0, node2 and node3:

node0 (NIC 4 and 5, bridged under br0, no IP addresses assigned to them):
NIC 1: MAC: 08002725B44E, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 2: MAC: 0800279A4C9C, Attachment: Host-only Interface 'vboxnet0', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 3: MAC: 080027A3617B, Attachment: none, Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 4: MAC: 08002739FF06, Attachment: Internal Network 'n0n2', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 5: MAC: 080027D5FF43, Attachment: Internal Network 'n0n3', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 6: MAC: 0800278895F5, Attachment: Internal Network 'n0n1', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps

node2 (NIC 4, IP address 10.0.37.2/24):
NIC 1: MAC: 080027205FBB, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 2: MAC: 080027D22B96, Attachment: Host-only Interface 'vboxnet0', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 3: disabled
NIC 4: MAC: 080027457D27, Attachment: Internal Network 'n0n2', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps

node3 (NIC 4, IP address 10.0.37.3/24):
NIC 1: MAC: 080027448B09, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 2: MAC: 08002795923F, Attachment: Host-only Interface 'vboxnet0', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 3: disabled
NIC 4: MAC: 080027052EC9, Attachment: Internal Network 'n0n3', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps


From my understanding of internal network mode, if I put two machines on different internal network, then they should not speak to each other. Thus, if node2 and node3 want to
exchange some data, that should only happen via node0. However, what I see is node2 and node3 ping each other without going through node0.

How can I fix this?

PS: Because I also want to ssh into each of the VM and download softwares from internet, I have also given each of them one NAT and one HOST ONLY adapter as can be seen
from the output of the above showvminfo command.

Similar setup (with same topology) on actual physical machines - with a different control network (for sshing and accessing internet) and data network (to transfer data between machines) - works fine.