What is System IP Address?

I want to know about system IP address, my question is, which department or company in Pakistan monitor the IP Addresses and locations of computers who send E-Mails  to  different users throughout the country or world. I want to locate a person who have sent an e-mail. i am going to develop an E-mail server that will keep track of user along with their location.

We appreciate your anticipation and such type of questions. In Pakistan the PTA is the governing body related to the Internet and telecomm it is a watch dog for restricting the IP addresses like now days of YouTube. But currently they have noting to do with the assigning of live IP addresses as internationally The Internet Assigned Numbers Authority (IANA) is responsible for the global coordination of the DNS Root, IP addressing, and other Internet protocol resources. The Local Internet service providers ISPs and webhosting companies are coordinating with it for the purpose of registering the Live IP addresses for them and then they may distribute the IP addresses locally to the end users and the small ISPs.

            Both PTA and ISPs will also be maintaining the location and addresses of the IP assigned organizations.