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elessargr , 08-30-2026, 08:40 AM

Hello all,

I have been working on a personal project that includes an Ethernet adapter for networking connectivity. The IC that I am using (RTL8153B) does not include a MAC address by default.
So after some reading around I was able to find out that I can purchase MAC addresses from IEEE (https://standards-support.ieee.org/hc/en-us/articles/25905800652180-MA-S-Qty-Price) though I am not fully sure if I need them for my project yet.
I have seen that quite few networking adapters that has pass through my hands do not actually have MAC addresses registered looks like (OUI, etc).

So if I chose to start selling the product as prototype is it require to have an official MAC address for each NIC or a random MAC would be good?

I have done some research that if a MAC address is doublicate in a network can cause issues though for the prototype phase maybe its okay to proceed without adding this additional expense?

Any advise would be greatly be appreciated!

Thank you!

, 08-30-2026, 08:43 AM

🤖 In the meantime, here’s a response from the [FEDEVEL AI HW Assistant]().
It helps to find relevant resources for your question, but it may make mistakes as it’s still in early development.

This is the response from the AI Assistant:
For Ethernet-enabled products, MAC addresses become legally required when you commercialize the device - prototypes can use random addresses temporarily but you'll need official IEEE-assigned addresses before market release. Here's the breakdown:

1. **Prototype Phase**:
You can use locally administered addresses (L2 bit set) with random values. While this risks network conflicts if multiple devices share the same MAC, it's acceptable for limited testing. In FPGA implementations, developers often hardcode test MAC addresses like in [this Ethernet tutorial](https://www.youtube.com/watch?v=78tkdc6Lq_8&t=2067).

2. **Commercial Sales**:
IEEE requires purchased MA-S/OUI blocks for any product sold with networking capabilities. The RTL8153B being a MAC-less PHY means YOU become the MAC address assigner. Regulatory certifications (FCC/CE) will verify proper MAC implementation - using random addresses would fail compliance as shown in [FCC certification discussions](https://www.youtube.com/watch?v=CTPb7etzOmA&t=4817).

3. Practical Considerations:
- Purchase at least a /36 MA-S block (4096 addresses) from IEEE
- Store addresses in secure non-volatile memory
- Implement address rotation if exceeding purchased block
- Validate uniqueness through manufacturing programming

While some cheap adapters use cloned MACs, this violates IEEE standards and risks network instability. For professional products, proper MAC management is essential from early production stages.

You can continue chatting with the AI Assistant here:
https://fedevel.com/hw-assistant

Robert Feranec , 08-31-2026, 10:11 AM

i am not expert for this, but if the chip is not coming with MAC and you are selling a commercial product, you may need to buy range of MAC addresses - we had to do this for the products in the company where I used to work. I think the same MAC may/will be a problem on local network (if the devices are on the same subnet), but I think it is not problem on Internet. Double check my answers.

QDrives , 08-31-2026, 07:01 PM

As you said, for prototyping it will not be needed.
However, when selling, I would use bought MAC addresses.
It is not that problems **might** happen when a duplicate is in the same network, they **will** happen.
Even if the chance of having a duplicate is low.