MAC Adress

[Boogyman]

Hello everyone,
I have the following problem. I would like to run 2 Truenas Scale servers in my network. Since both servers do not use the physical MAC of the NIC, I now have 2 times the same MAC address in the LAN. How can I change the default MAC address on at least one server?
There are 2 physical servers, each with a physical NIC. In my router, both servers are displayed with the MAC address 6C:B3:11:3D:4D:5E. The MAC addresses of my physical NICs are of course different. Truenas Scale exchanges the MAC for its own. Unfortunately they are the same, so my router plays ping pong.

 

[Ericloewe]

Since both servers do not use the physical MAC of the NIC

Why not?

 

[danb35]

Truenas Scale exchanges the MAC for its own.

That's certainly not the default behavior. Even with a virtual interface (like a LAGG), it takes the MAC address of the first physical interface.

The MAC address you gave appears to have come from Shenzhen Lianrui Electronics Co. (see https://mac-address.alldatafeeds.com/mac-address-lookup/B20w7vAvRm). It's not something TrueNAS would have assigned on its own, and it doesn't even look like TrueNAS even exposes an option to spoof a MAC address.

What hardware are you using for your NAS. Are you running it on the bare hardware, or virtualized? If the latter, which hypervisor?

 

[Boogyman]

I seem to have found the problem. I read in an Amazon review that I'm not the only one with this problem.

2.5 GBase-T PCIe 3.1 Network Adapter with Intel I225-V + 91 cm Cat8 Ethernet Cable 2500/1000/100 Mbps PCI Express Gigabit Ethernet Card RJ45 LAN Controller for Windows 10/11 with Low Profile Bracket
Brand: ULANSeN

 

[PhilD13]

It sounds like you have an issue with the router, or if you are running virtualized and created virtual network interface cards (VNICs) and somehow failed to assign MAC addresses to the virtualized network cards.

This is from Oracle:

A virtualized Network Interface Card is used by a Virtual Machine as its network interface. A VNIC is assigned a MAC address. Each MAC address corresponds with a single virtual NIC, which is used by a virtual machine. You create VNICs when you create a virtual machine. The Virtual NICs tab is used to display the VNICs assigned to different virtual machines within your environment and to control the MAC addresses applied to each VNIC.

 

[Ericloewe]

I seem to have found the problem. I read in an Amazon review that I'm not the only one with this problem.

2.5 GBase-T PCIe 3.1 Network Adapter with Intel I225-V + 91 cm Cat8 Ethernet Cable 2500/1000/100 Mbps PCI Express Gigabit Ethernet Card RJ45 LAN Controller for Windows 10/11 with Low Profile Bracket
Brand: ULANSeN

So, how are you determining the "real" MAC? Sticker on the cards? Did the fine engineers at Super China Happy Sun Shenzhen Technology Corporation Limited manage to program every one of their totally legitimate Intel NICs with the same MAC from the factory?

 

[Patrick M. Hausen]

So, how are you determining the "real" MAC? Sticker on the cards? Did the fine engineers at Super China Happy Sun Shenzhen Technology Corporation Limited manage to program every one of their totally legitimate Intel NICs with the same MAC from the factory?

 

[Boogyman]

Hello
here are some pictures

First Truenas Console
Second Unraid Console
Third MAC on NIC

 

[Ericloewe]

Oof. Notable reminder not to buy from the alphabet soup vendors that have inundated Amazon and other places.

 

[danb35]

That's frankly bizarre, and not something I ever would have guessed. But the same address showing in Unraid pretty conclusively rules out something with TrueNAS.

 

[Boogyman]

That's exactly how I see it. I have ordered 3 different network cards in different price ranges and chips. There should be a positive match.

 

[Ericloewe]

That's frankly bizarre, and not something I ever would have guessed. But the same address showing in Unraid pretty conclusively rules out something with TrueNAS.

I'm sort of surprised it took this long to come across such a brain-dead operation selling NICs. Apparently they knew they needed to register for a MAC block, but then shipped multiple NICs with the same address...

 

[anodos]

This is something that I've been seeing here some and in our jira (servers with multiple NICs with same MAC address). We'll probably all have more cautionary tales in the near future about buying cheap NICs off amazon, ebay, and less reputable places.

 

[Ericloewe]

As if I didn't have enough reasons to hate the 2.5 GbE ecosystem.

 

[Apollo]

It is expected to find identical MAC addresses across devices, simply because the MAC address itself cannot be unique with the gazillion of devices out there.
Either the same MAC address has been left untouched or replicated on purpose, or the MAC address assignment has been omitted, it should still be possible to program a second MAC address if the device has been designed to support this feature (this is different from spoofing, as far as I know).

 

[Ericloewe]

It is expected to find identical MAC addresses across devices

Not multiples in a single production run. The stickers with different MACs also suggest gross incompetence.

 

[Apollo]

Either the same MAC address has been left untouched or replicated on purpose, or the MAC address assignment has been omitted,

That's why I added this.

 

[Ericloewe]

That's what we call a ninja edit. One of the many perils of the internet...

 

[Boogyman]

Hip hip hooray, now it works.

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