Using the customer data protection mode you can define individual daily limits for accessing customer contact details. You can also check who viewed those details and when.
In order to do this, you need to go to settings > customers > Customer data protection > activity logs.
In order to track an IP address, you can use the following website: http://www.yougetsignal.com/tools/network-location/
Information on who exactly uses a particular IP address can be obtained exclusively from the internet provider.