What an IP lookup can and cannot tell you
Every public IP address belongs to a block that a registry assigned to an organisation: an internet provider, a hosting company, a university or a large business. The lookup returns that registration record: the organisation, the network name, the address range and the country where the block is registered. It does not reveal who was using the address at a given moment; only the provider holds that information.
Fields explained
- Organisation: the holder of the block (often a provider that then assigns addresses to its customers).
- Network / handle: the registry's name and ID for the block.
- Range and CIDR: the first and last address of the block, and the same block in CIDR notation. Use the subnet calculator to explore it.
- Registration country: where the block is registered, not necessarily where the device is.
- Abuse contact: the address to report spam, attacks or other abuse coming from this network.
- Reverse DNS: the hostname configured for the address (PTR record), which often reveals the provider or server role.
Private addresses
Addresses such as 192.168.x.x, 10.x.x.x, 172.16.x.x–172.31.x.x and 100.64.x.x (carrier-grade NAT) are not registered on the public internet, so there is nothing to look up. They identify devices inside a private network only.