A little known fact is that some browsers, including Chrome and Firefox, have an API that lets a website get the LAN IP address of a client (often of the form 192.168.x.x or other private IPv4 address). That info typically remains constant across uses, and allows to precisely discriminate among devices sharing the same network access point (e.g. fiber/cable/ADSL box).
To see this in action, head to whatsmyip.com and scroll down to the bottom left, "Your computer". Here is your LAN IP (and unless I missed something, it was not generated locally). That works with a default install of Chrome and Firefox, including in "private navigation" mode.
In Firefox, at least that way of obtaining the LAN address can be prevented by going to about:config
, getting past the warning, searching media.peerconnection.enabled
and setting that to false. If there are practical adverse effects, I did not find these in months of use.
Is there an equivalent setting in Chrome?
As an aside: I whish that would be the default, at least in "private navigation" mode.