Locate *physical* MAC address

[ahauerwas]

Hi, I work in IT at a college and am trying to figure out how to connect a Chromecast with Google TV to our campus network.  We have a wireless network for devices, but we have to whitelist the MAC address prior to connection.

In working with the Chromecast it appears as if it ALWAYS uses MAC address randomization -- even when the Privacy wi-fi settings say to "Use device MAC."  It appears as if the device MAC that gets used VARIES depending on which wi-fi network is connected.  I have two wi-fi networks at home, and saw a different "Device MAC address" for each of my home SSIDs that I connected to.

Additionally, documentation on how to find the MAC address requires that you first be connected to wi-fi -- which I can't do on-campus since I first have to whitelist the MAC address.

@JenniferV  and @Jeran have tried to help other users with similar problems and I can't tell if the users were ever successful or not; some users disabled MAC address authentication temporarily, or some connected to different wi-fi networks -- but those options are not possible for me, and none of the threads seemed to provide a consistent way to acquire a physical MAC address for this device.

Is it simply not possible?  And note:  I did try enabling developer options in order to disable MAC address randomization, but there was no option to do so under the Developer menu for the Chromecast with Google TV.

Thanks.

[JenniferV]

Hi ahauerwas,

I understand that the options provided in the threads you linked isn't possible for you however, since you have a Chromecast with Google TV, you will not be able to locate the MAC address during the initial setup. It must be set up first in a network in order to obtain it. 

Thanks,

Jennifer

[adamhauerwas]

So is what I want not possible?  I can’t connect to Wi-Fi if I haven’t preregistered the MAC address — and I can’t get the MAC address unless I connect to Wi-Fi. If that’s true, then we can’t use these devices on our network at all, and we can’t support anyone who brings one to campus. 

Additionally, I bought this because I wanted to cast video from a Meta Quest to the Chromecast as a receiver — but if that’s not possible then I will have to return the device and look for an alternate option. Do any Chromecast devices allow me to get the physical address?

[adamhauerwas]

PS: I want to reiterate: I HAVE connected to other Wi-Fi networks to TRY and obtain the MAC address — its just that MAC address randomization seems to be occurring, since the MAC changes with each network I connect to. I need to know and/or set the MAC address prior to connecting to a specific corporate network.

[JenniferV]

Hello there,

Thanks for getting back to us. To confirm, during set up, are you using a third party app such as a MAC address locator to locate the MAC address? If yes, that could be the reason you're getting a random MAC address for the device. 

On the other hand, if you're not using another app to locate it, please share a screenshot so we can get a better picture of the issue. Please remove any personal information such as the IP address if it will be shown in the screenshot.

Thanks,

Jennifer

[JenniferV]

Hey ahauerwas,

It's me again. How's it going? Do you still need help?

Regards,

Jennifer

[adamhauerwas]

Jennifer, the Chromecast is at work and I'm on PTO with the holidays.  I'll ping the thread now to keep it alive and will get pictures of the MAC address displayed when on wifi next week once I have access to the device again.

[JenniferV]

Hello adamhauerwas,

Got it — sounds like a plan! I'll wait for your update.

Best,

Jennifer

[JenniferV]

Hi there,

I don't want to be a nudge, but I'd like to check if you were able to get the needed information. Don't hesitate to reach back if you still need help.

Thanks,

Jennifer

[ahauerwas]

Jennifer, I connected the Chromecast to two different wifi networks in order to demonstrate what I was talking about.

I connected to one wifi network called "Ticker" and my MAC address was a6:87:dd:fc:8e:e7; you can access that image at https://drive.google.com/file/d/1J_zjPpnCVul-mxnc1u9cv7O6I5S42a6G/view if the imbed does not work:

I then connected to a wifi network called "PC-Academic" and my MAC address was f6:35:fb:79:36:b0 (see https://drive.google.com/file/d/1m3V9WeqH_K3pfvs0ZhoYbgr_jDdCFA7U/view😞

Lastly I went to System Status to see what the system thought it's MAC address was -- that was 38:86:f7:31:e3:2a (see https://drive.google.com/file/d/1sp-4ymxJ4kkgPahXU-JuqTbYHOgSiNjW/view😞

I need to know the MAC address for the device before connecting to wifi in order to be able to whitelist the device in my wireless infrastructure.  Is it possible to know what the MAC address will be?

[JenniferV]

Hey ahauerwas,

Thanks for the information. I'll check this with our team and get back to you once I hear any update from them — hang tight!

Best,

Jennifer

[InterestingGuy]

Hi, I also have this problem.  I've tested two Chromecast devices so far (a 2016 model and current HD 2022).  My building network provider says I need to 'register the MAC address' to allow the device over Wi-Fi.  I have found the MAC address of both Chromecasts by tethering them to my 4G phone and setting them up that way then going into Wi-Fi setting where you will then see the physical MAC address and IP.  The problem is that even the older device has now had a firmware update, so there is no way of knowing whether 'MAC address randomization' is in place on the device itself.  So now they say they can't connect it to the network and are considering not supporting them over their Wi-Fi which is not good for me.  So I'd be interested in the outcome of this one if Google ever solves it.

[JenniferV]

Hello folks,

Update! Our team checked this and informed me that the device will connect to the MAC filtered network, but can't access the Internet initially as it defaults to randomized MAC. However, it will allow you to go to GTV settings and "Use device MAC". You may need to toggle to randomize MAC first then toggle back to Use device MAC. Check the detailed steps below:

1. To fully set up the device on an open network to receive the OTA.
2. Complete setup of the device.
3. Go to the Chromecast with Google TV Settings and try to connect to the MAC address filtered network.
4. The connection will fail because the MAC address is randomized, but this will allow you to switch to using device MAC and then re-connect to the network. Toggle to randomize MAC first then toggle back to Use device MAC.

Best,

Jennifer

[ahauerwas]

Hi, Jennifer.  I appreciate your conferring with the team and finding these steps -- though they seem to be a "workaround" at best and not exactly a solution.

Your step (1) requires that we first connect a new Chromecast to an open network for initial set-up and to retrieve the device MAC address.  That may not exist in every organization -- and it's a step that people bringing devices to campus may not have performed before coming to school.

Additionally, once we have the MAC of the device (I assume by going in to Settings) we then have to connect to the MAC-address-filtered network and FAIL CONNECTION before we can turn of MAC address randomization.  That seems...bass-ackwards.

I would suggest to the developers that there should be options in the initial set-up to allow for MAC address randomization to be turned on or off -- an Advanced Settings menu.  Without that, I don't see how we could support these devices in our collegiate environment...

[JenniferV]

Hi ahauerwas,

We hear you and we appreciate your feedback. Rest assured that we'll learn from this to deliver a better process and experience in the future. You can also send feedback about this using the Google Home app. Here's how.

Let me know if you still have questions and concerns otherwise, I'll be locking this thread after 24 hours.

Best,

Jennifer