MAC randomisation and DHCP pools

Michael De Roover isc at
Fri Jul 24 17:28:49 UTC 2020

On 7/24/20 11:48 AM, glenn.satchell at wrote:
> This is not something new, it has been around since IOS 8 in 2014. I 
> think this page summarises how it works and has links to Apple's site 
> with more details.
> It appears that it randomises the MAC address when the device is 
> passively scanning for networks and other particular settings are 
> enabled or disabled, so systems can't use the MAC address to 
> persistently track wherever you go. However, it seems that any 
> associations/joining of networks is based on the actual MAC address.

On Android this has also been implemented since either 9 or 10 I think.. 
not 100% sure. In it the option to use the real device MAC can be chosen 
on a per-network basis though. By default both the discovery and the 
eventual connection have the MAC randomized. So for my DHCP server which 
gives static leases based on the MAC address, making it use the real MAC 
ended up being imperative. I really hope that this option will not be 
removed. Development on ISC dhcp seems to have pretty much ended since 
about half a year ago, so if it does get removed client-side I'd 
probably have to rethink the server side.

Met vriendelijke groet / Best regards,
Michael De Roover

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