User identity - problem
 

Hello. I apologize if the section is not suitable. I would ask the moderators to move it.
I write this post to share with you an issue. I am a Administrator in the forums with vBulletin vers. 4.0.1 I was wondering if you could somehow go back to the entry of a user. Let me explain, in addition to displaying the IP registration, but if you register with other IP or maybe use a provider where the ip changing. It 'can be traced back in some way restricting the user's identity in writing? Maybe with some code or other?
Thanks