How would I go about mapping a prefix to an organization? I know I can use whois to map a given IP address to its AS and organization, but what about a prefix (as in, IP and some netmask)?

Lets say provider A owns the prefix and sells to company B. Now if I lookup the IP 192.1.0.x I will get company B. But what If I specifically want to find out who owns So far all the services I've found only map IP's to organizations, but not prefixes. Is there any way to get this information?

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    Commented Jan 6, 2021 at 2:45

2 Answers 2


Every whois service provides different option to specify which information you want. I have most experience with the RIPE database. There is a web interface available, but the most direct way to access the information is using the command line. You can request help using this command:

$ whois -h whois.ripe.net -- -h

There you can see the option that you need:

%     -L, --all-less <ip-lookup>
%           Returns all level less specific inetnum, inet6num or route(6)
%           objects, including exact matches.

If I request information about my own address (yes, I am my own ISP):

$ whois -h whois.ripe.net -- '--all-less'
inetnum: -
netname:        IANA-BLK
descr:          The whole IPv4 address space
inetnum: -
netname:        EU-ZZ-37
descr:          RIPE NCC
descr:          European Regional Registry
inetnum: -
netname:        NL-STEFFANN-20120201
descr:          S.J.M. Steffann
inetnum: -
netname:        STEFFANN-OFFICE1
descr:          S.J.M. Steffann Office

And you can see the whole hierarchy. The web interface shows exactly the same information.


You can check your RIR's whois database. For example, if you go to www.Arin.net and enter an IP to search in their who-is, the record should provide a link to the parent.

Have a look here for more info: https://www.arin.net/resources/whoisrws/index.html

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