Most of the users on my forum have fixed IPs. Is it possible to log each unique IP a user uses to log into their account?

I tried searching but didn't find anything suitable. I'm not too bothered about users having multiple accounts, and I know I have several families on my board with each member having their own account, which would give a lot of false positives anyway.

What I'm trying to track is account sharing.

I have v7.2.2 with a current license, so I'll be able to get v7.3 when that's finalised, if someone knows of something that will work for that!

There was a mod like that prior to version 7, don't think anyone has worked on re writing it though.