How do I deal with duplicate MAC addresses on a network

BotBlox Hardware
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– Copied from an email –

After review of your website, I am currently interested in your BB-SWR-F-1 in a managed switch application. In my test environment I have an unavoidable / unchangeable duplicated MAC address across multiple LAN devices which causes network issues and collisions for obvious reasons.

With the BB-SWR-F-1 or smaller managed switches, is it possible to reassign MAC addresses on boot? This is similar to “clone MAC address feature on some retail boxed routers. If this possible how would this be implemented (firmware, code, webpage, configuration file, etc…?

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If I correctly understand the “Clone MAC address” feature you mention, this is a feature that allows you to copy a MAC address of a device to a different piece of hardware.

What Is MAC Cloning and Why Do It?.

The issue you have described is that you have multiple devices on your network with the same MAC address. If I understand correctly, Cloning MAC address would not solve your problem, in fact, it would be the opposite of what you want.

According to the link below, there is no “proper” solution to connecting two devices with the same MAC address on the same IP network.

How to solve problem with two devices with the same MAC address, connected to the switch? - Network Engineering Stack Exchange.

This post suggests using VLANs to segregate the traffic logically (the device won’t see each other), and then using a router to control the flow between them.

Note that a Switch is a Layer 2 device, while a Router is a Layer 3 device. Nearly all of our products are switches.

We are developing Rugged SOM, which stacks together with SwitchBlox Rugged to form a device that can operate as a router. However this product is beta and it will be a few months until it can be configured to operate as a router the way you might want.

In terms of how such a system would be configured, it would be over SSH into Rugged SOM, which runs embedded linux and can be used to configure the switch chip on SwitchBlox Rugged entirely. That being said, I believe to solve this you’d need to first implement VLANs on SwitchBlox Rugged, and then have some software running on Rugged SOM to implement the “go-between” of both VLANs.

Alternatively you could connect a seperate router directly to one of the ports on SwitchBlox Rugged. If you had, say, two devices with the same MAC address, this means you’d have two VLANs… say…

Device 1 (MAC Address: 11.22.33.44.55.66) on VLAN1
Device 2 (MAC Address: 11.22.33.44.55.66) on VLAN2
Router (MAC Address: “Something else” on VLAN1 and VLAN2

If your router was some embedded computer, you could write some software to implement the go between, which may involve manually spoofing the MAC addresses.

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