How To Use an IP Address and Whois Tool to Find a Site's Contact Information

Useful Information to Find Who is Behind an IP Address

The Internet Protocol (IP) is a piece of software running in your operating system that is basically in charge of two things: identifying your computer and routing data.

To perform the first task, the IP protocol must mark each packet of data with two pieces of information: where the packet comes from and where is it going to. The "marks" of the origin and destination of every packet are identification numbers, called IP addresses.

Every host on the Internet must have an IP address. If you are a home user, your Internet provider will take care of this, sending you a dynamic address every time you get connected. So if you receive something from someone on the Internet, the first thing your computer will "see" is a number. Depending on the type of connection, it may be an HTTP response for a site you are accessing, an e-mail message arriving to your mailbox, a chat response from a friend, a phone call for you, or any other type of communication.

If you get suspicious of an IP address and want to know which organization is using this address or where in the world the person using this account is, this article is for you. The next steps will summarize a procedure to find an IP address and who owns it.

  1. Open your browser and point it to a "whois" tool. A "whois" tool is a way to search inside the DNS (Domain Name System), a distributed database of domains (such as "", "", etc.), computer names in domains (such as,, and so on) and their IP addresses. If a computer is not a server, like a web server and an e-mail server, most of the time it will not have a name registered in the DNS. But its IP address belongs to someone and the "whois" tool will inform you which organization it belongs to. As a suggestion, you can use the Geektools whois page.
  2. Enter the domain name or IP address of the site in the search field. Type it in the search box. Let´s find who is behind the address, for example. (You can also search by domain name, like, if you do not know the IP address.)
  3. Analize the response. The whois tool will search DNS databases over the Internet and will print out the results. If you are curious and want to know where the result was found, check the text "Final results obtained from" in the response you got. In our example, it was answered by the server called "". Following the "OrgName" description you will see the name of the company this address is registered to. In our example, our friends from Google.

    In the "NetRange" section you can see the network range this address belongs to. If you are not a Network administrator, it will not interest you very much ;-). If you continue to roll out the page, you will get to the phone number, e-mail and the contact name of the person who has registered this domain in the Internet. Of course, some companies choose not to inform detailed information here.

Note: If you want, you can search by domain name instead of an IP address. Try to search for a domain name like "" and check the results.

Alessandro Loesch Jannuzzi

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