My online banking web site can uniquely identify computers (Windows OS) on my home LAN.
Identity confirmation is done for each web browser on the computer. That is, when I try to access their web site the first time from a specific computer, they ask me to confirm my identity by sending me a specific code that I have to enter on the web site. Once I have entered the code, the next time they remember my computer/web browser. This is an extra security measure in addition to supplying username/password.
How is it done?
Could it be a unique HTTP header that I am not aware of? Or is it something more sophisticated at the low level like MAC address? As far as I know, with IpV4, MAC addresses don't get outside of LAN.
It could also be some unique fingerprinting algorithm that uses a combination of parameters.