How to disable MAC address randomization?

[cyberstudio]

Couldn't find in the Ventura (OCLP) UI... There seems to be no "Private Wi-Fi-address" setting. iMac Late-2013 OCLP 13.5.1.

I didn't need this privacy feature to protect me from my own home network, because an iMac can't move or connect to a public Wi-Fi... I am having difficulty with wake-on-lan.

Thanks in advance for your help!

 

[adrianlondon]

My understanding is that MacOS doesn't have that feature; the MAC address is never changed. It certainly doesn't on my laptop.

 

[bogdanw]

MAC address randomization is "Available in iOS 14 and later, and watchOS 7 and later."
https://developer.apple.com/documentation/devicemanagement/wifi

Instead of using DHCP, try to set the IP manually.

"Use DHCP or a manual IP address on Mac"
https://support.apple.com/en-us/guide/mac-help/mchlp2718/mac
https://support.apple.com/guide/mac-help/mchlp2718/mac

 

[HDFan]

Instead of using DHCP, try to set the IP manually.

Is there a reason you suggest this? The MAC address is in a lower network layer and shouldn't be affected by an IP address change.

 

[adrianlondon]

MAC address randomization is "Available in iOS 14 and later, and watchOS 7 and later."
https://developer.apple.com/documentation/devicemanagement/wifi

Instead of using DHCP, try to set the IP manually.

"Use DHCP or a manual IP address on Mac"
https://support.apple.com/en-us/guide/mac-help/mchlp2718/mac
https://support.apple.com/guide/mac-help/mchlp2718/mac

As mentioned by HDFan (should upgrade to 4KFan!) the IP address and MAC address are different things. As you say, IP addresses are allocated by DHCP unless set manually (either in the O/S or by the router) whereas MAC addresses are typically tied to the network interface itself.

For those interested in the details:

For a computer, there will probably be two MAC addresses - one for WiFi and one for Ethernet. Since iOS14, and it's a great feature, the phone generates a different MAC address each time it connects to a network. In other words, it doesn't just keep using the MAC address tied to the WiFi chip inside the phone. That's great to stop you being tracked as you wander around connecting to free WiFis in cafes etc.

This can be bad for home WiFi networks, though. The reason is that there are people (such as me) who always want their devices to have the same IP address so we can easily connect to them from other devices at home. And routers use the MAC address to determine whether it's the same device as before (hence giving the same IP address before, especially if hard-coded and not using DHCP) or a new device (which gets a new IP address).

 

[bogdanw]

"Consider setting a static IP address on the Mac rather than using a random DHCP assigned IP"
https://osxdaily.com/2013/12/14/wake-on-lan-mac-iphone/

 

[HDFan]

Since iOS14, and it's a great feature, the phone generates a different MAC address each time it connects to a network.

Not able to reproduce. Switched between 3 networks, rebooted. WiFi address stayed the same.

 

[bogdanw]

Not able to reproduce. Switched between 3 networks, rebooted. WiFi address stayed the same.

If the "feature" doesn't work, "Reset your network settings" https://support.apple.com/en-us/HT204051
Wi-Fi privacy - MAC address randomization https://support.apple.com/guide/security/secb9cb3140c/web

 

[HDFan]

Wi-Fi privacy - MAC address randomization

"Apple platforms use a randomized media access control address (MAC address) when performing Wi-Fi scans"

 

[bogdanw]

"Apple platforms use a randomized media access control address (MAC address) when performing Wi-Fi scans"

You didn't read to the end
"Apple platforms use a randomized media access control address (MAC address) when performing Wi-Fi scans when not associated with a Wi-Fi network."

"Because a device’s MAC address changes when disconnected from a Wi-Fi network, it can’t be used to persistently track a device by passive observers of Wi-Fi traffic, even when the device is connected to a cellular network. "

"In iOS 14 or later, iPadOS 14 or later, and watchOS 7 or later, when an iPhone, iPad, iPod touch, or Apple Watch connects to a Wi-Fi network, it identifies itself with a unique (random) MAC address per network."

and more
"To communicate with a Wi-Fi network, a device must identify itself to the network using a unique network address called a Media Access Control (MAC) address. If the device always uses the same Wi-Fi MAC address across all networks, network operators and other network observers can more easily relate that address to the device's network activity and location over time. This allows a kind of user tracking or profiling, and it applies to all devices on all Wi-Fi networks.
Starting with iOS 14, iPadOS 14, and watchOS 7, your device improves privacy by using a different MAC address for each Wi-Fi network. This unique MAC address is your device's private Wi-Fi address, which it uses for that network only.

In some cases, your device will change its private Wi-Fi address:
If you erase all content and settings or reset network settings on the device, your device uses a different private address the next time it connects to that network.
Starting with iOS 15, iPadOS 15, and watchOS 8, if your device hasn’t joined the network in 6 weeks, it uses a different private address the next time it connects to that network. And if you make your device forget the network, it will also forget the private address it used with that network, unless it has been less than 2 weeks since the last time it was made to forget that network."
https://support.apple.com/102509

 

[HDFan]

Got it. Thanks for the explanation.