I have following network setup.
When the link marked by red cross is up, I can ping from first machine (10.1.1.7) to second machine (10.1.1.3) without any problem. However, if I take down that link and try to ping from first machine to the second, I see that arp queries come for ip address 10.1.1.3 on the second machine's second interface (10.1.3.2) but it does not reply to those queries. This is expected I think as that interface does not know about other interface's ip address.
But if I still want to make them connect, I think I need to set some value in one of the: /proc/sys/net/ipv4/conf/(default|all)/arp_*
But which one? I played around setting some of them but did not work. Any help related to this would be greatly appreciated.
** UPDATE **
Actually let me clarify the problem. What I really want to do is start a file transfer from first machine to the second. The transfer should happen over the link marked by cross. In the middle of the transfer, I will take down that link. Transfer should automatically switch to other links. You can suggest me any changes to IP addresses etc.
What I tried is: On machine 2, I kept both MAC interfaces on the same subnet. That is NIC1: 10.1.1.3 NIC2: 10.1.1.17
Then I created a software bridge on machine 2, gave it IP address 0 and added NIC1, NIC2 under it. My idea is bridge will flood the queries received on NIC2 to NIC1.
Now I have a new problem. When I add both NICs to the bridge, they stop responding to ARP queries even if the link is up.