How can I determine who is responsible for a particular IP address or domain?
Sometimes you may want to find out who is responsible for a particular
IP address or domain name. For example, if you
are getting junk mail from several email addresses that end in
@mango.net, you may want to get an address for the system
administrators at Mango Net to ask them to stop this. Or, if you
think your computer has been broken into by another computer having
the IP address of, for instance,
184.108.40.206, then you
may want to find out what organization is responsible for that IP
If you are a student, faculty member, or staff member of Indiana University who needs access to IU's central systems from a computer outside the IU network, you may need to contact the outside system's network administrator for help. Receiving a bad IP address is the most common reason for needing to contact an outside network administrator. For example, if you dial into a local Internet service provider called Mango Net, and you are unable to access your IU email account, Mango Net may have assigned you a bad IP address. The Mango Net system administrators will need to fix this for you.
The American Registry for Internet Numbers (ARIN) provides a Whois utility that you can use to find the system administrator of a particular IP address or domain. You can access this utility at: https://www.arin.net/ In the "SEARCH Whois" field at the top right, enter the IP address or domain IP address in which you are interested.
An example of an IP address is: 220.127.116.11 This would be the IP address for a particular computer at IU.
An example of a domain IP address is: 18.104.22.168
All computers that start with
129.79 are in the
Domain IP numbers can be of variable length. For example, for a small organization, the domain IP address might be: 22.214.171.124 A very large organization needing more individual IP addresses might have a domain IP address of just: 126.96.36.199
Last modified on February 19, 2013.