Admin feature: Check for multiple accounts

[lithanual]

I would love it is SMF logged every IP a user has used and generated a list on demand of all users who have used the same IP.

[Oldiesmann]

This can already be done by going to the user's profile...

To see all IPs used by a user: Click on "Track User"
To see all users with that IP (or a similar one): Click on "Track IP"