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 a specific IP address, you may want to find out what organization is responsible for that IP address.

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.