tracking by ip address is for the lazy, and it doesn't work with dynamic IPs. at least not if the goal is to eg limit your access to how many articles you read per month. you'd not be happy if you go to a site for the first time but are blocked because you got a new IP that has already been to that site 5 times this month.

i'd use full browser/device fingerprinting to achieve the same effect. much more reliable.