IP lookup. Look up who holds an IPv4 or IPv6 address in the regional internet registries' public RDAP records (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC): the holding organisation, network name and range, allocation type, registration country, abuse contact and registry. Use to see which company or ISP a log or firewall address belongs to. Registration country, not city geolocation. Private and reserved addresses are refused with 400, uncharged.