Nigel Carson, a computer forensics investigator, said that it was possible to locate the physical computer and user of the machine by tracing the IP address. Carson said that IP addresses usually change when a dial-up connection is involved. However, most of the time, users with broadband and cable Internet connections use only one IP address.
Carson also added that even when IP addresses change, the user can still be tracked down to the Internet service provider where the user information can be collected.
Carson said that if a company, like Sharman Networks, wants to trace a specific user who shared unlicensed music files, they would need to store the date and time that the transaction was done.
However, Carson said that companies usually needed a legal order before they could obtain user information from an Internet provider. Carson also admitted that he saw a copyright warning before he himself downloaded the Kazaa software.
When questioned by major music labels' lead barrister Tony Bannon, Carson said he was not familiar enough with the Kazaa software to be able to answer if it has remote trigger capability -- being able to terminate a users' connection -- but said that type of technology exists.
The morning was taken up by legal arguments on what evidence proposed by the applicants is admissible in court. Justice Murray Wilcox declared significant passages of the applicants' affidavits as inadmissible because of lack of evidence or lack of relevance to the case.
The previous version of this story indicated that Carson was employed by KPMG. While he previously conducted Internet investigations for KPMG, he is presently a director of Ferrier Hodgson.