Transparent ARP bridge

RouterOS General
1

Hi, I want to make a bridge between ports 4, 5, 6, 7, 8 and 9, in a RB2011 model, with firmware 6.27. The problem is that the devices that are connected to this router doesn’t see the mac-address of the other devices but the mac-address of the mikrotik bridge, when they use ARP, so it is making kind of arp-proxy between the devices in the bridge.

I have found the possibility to set arp=transparent in the bridge settings, in firmware v2.4, but I don’t find this command in the current version.

Is there any other way to do it or something that let the devices connected to the bridge see the others’ mac addresses with ARP?

Regards!

Cristian

2

I have the setting in my bridge set to proxy-arp and I can see all devices on the lan through the bridge.

3

Thanks for your reply, I also can see all the devices, but the problem is that they don’t see each other. I talked to support and they said that with arp=enabled it should be transparent but maybe because of the hotspot it is not transparent. However, they didn’t give me a solution, ¿anyone knows how to solve it?

Thanks

4

You need to configure a real bridge on your system.

In the ethernet interfaces configuration, make sure that ports ether1 - ether5 have master port set = none
Then set port ether5 master = ether4

Next, make sure port ether6 has no master, and ether7 - ether9 have master = ether6

so 5 master → 4
and 7-9 master → 6

Now make a bridge interface.
In Bridge > ports configuration, add ether4 and ether6 as ports to this new bridge.
This bridge is now your LAN.
Make sure your LAN IP address, dhcp server, hotspot, firewall rules - anything having to do with LAN is configured to use the bridge1 interface.

Anything plugged into any of these ports will now be able to see each other with the conrrect MAC address.
Make sure arp type is just set to normal “enabled” mode on all ports and the bridge port.

5

The way that a hotspot works by default is that it does do proxy-arp so that when a client comes into the network with wrong settings, it can act as if it is the default gateway they are trying to talk to and service their requests.

To turn this off you need to set the address pool to “none” under the hotspot server settings. Just keep in mind that you then loose the above functionality. The hotspot will still work, but the client needs to have proper IP settings to communicate to the internet.