Master and slave devices talking to each other through another device with two interfaces. All in the same network

Question

I have three devices, one is a master which will talk with the slave and Device3 but it is only physically connected to the Device3. The slave will speak only with the master(also through the Device3). The third device is meant to be a gateway between master and slave, but also receive commands from the master.

They are all on the same network. Lets suppose:

Master - 192.168.0.1(eth0)

Slave - 192.168.0.2(eth0)

Device3 - 192.168.0.3(eth0) and 192.168.0.4(eth1)

How can I make this work? Device3's OS is Linux. I suppose I will have to set ARP filter and routes to both eth0 and eth1, right?

echo 1 > /proc/sys/net/ipv4/ip_forward on device3 is not enough ? route add default gw depending on which side you are. — Nabil Bourenane, Apr 02 '15 at 15:39

score 0 · Answer 1 · answered Apr 02 '15 at 22:40

In general, TCP/IP based networks expect all machines in the same subnet to be directly reachable. You break this rule in your setup.

Configure two subnets, 192.168.0.x for the master and 192.168.1.x for the slave, set up device3 to forward packets (router functionality) and tell master that in order to reach 192.168.1.x use device3 as the gateway, and tell the slave that in order to reach 192.168.0.x use device3 as the gateway.

Master and slave devices talking to each other through another device with two interfaces. All in the same network

1 Answers1