What is an IP netblock? How to find netblock owner?

A netblock is a range of IP addresses like 190.255.0.0 - 190.255.255.255. They can also be represented in CIDR (Classless Inter-Domain Routing), where the above would be 190.255.0.0/16.

You can find the netblock owner or a range of IPs owned and operated by a company using IPInfo.io IP ranges API.