Faulty network nodes have identical MAC

RouterOS General
1

Hi!

I am working on a simple network with one server and nine nodes working on the same subnet via the switch. The server (node N1) has to have internet access (for remote maintenance, teamviewer), so a 4G router is connected. Other than maintenance, there is no need for internet communication (the system is closed). There is a diagram attached below.

The problem is that three nodes (N7, N8 and N9) have identical MAC because of the manufacturing fault, and they can not work on the same switch. The nodes are elementary devices, and it is impossible to change the MAC on them. Replacing the devices with new ones would take forever and is not an option.

I have a Mikrotik router on site, so I thought about using L3 to work around the identical MAC problem. I have attached a diagram of the system with the added router.

The problem is that I am having issues with adequately configuring the router. I’ve put the bridge between port1 (wan) and port2 (switch), but that has cut off the faulty nodes (N7-N9).

Any suggestion on altering the Mikrotik configuration to fulfil all the requirements is most welcome.

This is the current config:

/interface bridge
add name=bridge1
/interface bridge port
add bridge=bridge1 comment=switch interface=ether2
add bridge=bridge1 comment=wan interface=ether1
/ip address
add address=192.168.1.1/24 interface=ether2 network=192.168.1.0
add address=10.1.7.1/30 interface=ether3 network=10.1.7.0
add address=10.1.8.1/30 interface=ether4 network=10.1.8.0
add address=10.1.9.1/30 interface=ether5 network=10.1.9.0
/ip dhcp-client
add dhcp-options=hostname,clientid disabled=no interface=bridge1

The requirements are:

  1. node1 (server) has access to the internet
  2. node1 (server) and nodes 2-9 have TCP communication

Thank you!


Initial config

Config with router inserted

2

I figured this out. I’m posting the configuration, in case someone runs into this kind of issue (switching with devices with identical MAC addresses).

/ip address
add address=192.168.1.1/24 interface=ether2 network=192.168.1.0
add address=10.1.7.1/30 interface=ether3 network=10.1.7.0
add address=10.1.8.1/30 interface=ether4 network=10.1.8.0
add address=10.1.9.1/30 interface=ether5 network=10.1.9.0
/ip dhcp-client
add dhcp-options=hostname,clientid disabled=no interface=ether1
/ip firewall nat
add action=masquerade chain=srcnat out-interface=ether1
/ip route
add distance=1 dst-address=10.1.7.0/30 gateway=ether2
add distance=1 dst-address=10.1.8.0/30 gateway=ether2
add distance=1 dst-address=10.1.9.0/30 gateway=ether2