1 PC 2 NICS, can they be on same subnet

[ernesth99]

Hello.
I have a simple network consisting of 3 nodes (NODE 1, 2 and 3), all of them Windows XP Pro machines.
NODE1 has 2 network cards and NODE2 and NODE3 have 1 network card. I want to have it so I can have two separate networks with NODE1 able to see NODE2 and NODE3, but with NODE2 and NODE3 only able to see NODE1.
I have the first NODE1 nic and NODE2 connected to a hub, and the second NODE1 nic and NODE3 connected to another hub. All of the nics are configured with a static ip address, subnet mask = 255.255.255.0, no default gateway. The ip addresses are as follows:

first NODE1 nic = 25.55.1.2
second NODE1 nic = 25.55.1.3
NODE2 = 25.55.1.1
NODE3 = 25.55.1.7

With this configuration (I have tried it with a couple sets of PCs), there is always one nic that is not able to be seen on the network. For example, NODE1 can see both of the other nodes, but only NODE2 can see its NODE1 nic; or NODE1 can see NODE3 but cannot see NODE2, NODE3 can see NODE1 but NODE2 cannot. If I separate out one of the NODE1 NICs and one of the other nodes into their own subnet, then everything works fine. I need to have this configuration because that is currently what is called for in the network designs (this is actually a SCADA, view node, and PLC network).
Can I have all of them on the same subnet, and if not, why exactly. I have read in a few places that they need to be on separate subnets, but I need to have a definite reason why in order to change designs and make a new standard, and that I have not seen. Or, is this possible through using different subnet masks, default gateway, etc? Any help would be appreciated.

ernesth99

 

[sab4you]

you can have them on the same subnet, but where the problem lies is NetBIOS.

You can only have one computer name in NetBIOS, and if you have two interfaces, its going to say there is already a computer with that name on the network

You will have to disable NetBIOS on one of the network interfaces, but because of this, when you browse the network neighborhood, it uses NetBIOS broadcasts to determine who's on your network - and will obviously not see the interface with NetBIOS turned off.

You can still connect to this computer on both interfaces, just so long as you simply use the IP address, not the computer name.