>>14221>>14224To be specific, the MAC address of the WAN interface on your router, that is probably the different colored single ethernet port on your router that you plug into your modem instead of PCs. You can most likely change this through webpage configuration of your router, which you can access by entering the address of your router into a web browser.
https://www.howtogeek.com/179700/beginner-geek-how-to-configure-your-router/This explains how to do it on Windows, if you're on Mac or Linux, simply type "route" into a terminal and enter that IP address into a browser.
Everytime you connect to your ISP it checks to see if the MAC address you're connecting with has already connected before, and if so it gives you the same IP address.