Whois Database
The APNIC Whois Database contains registration details of IP addresses and AS numbers originally allocated by APNIC. It shows the organizations that hold the resources, where the allocations were made, and contact details for the networks. The organizations that hold those resources are responsible for updating their information in the database. The database can be searched by using the web interface on the APNIC site, or by directing your whois client to whois.apnic.net (for example, whois -h whois.apnic.net 203.37.255.97).
Read more about this topic: Asia-Pacific Network Information Centre