IP addresses are assigned by the Internet Assigned Numbers Authority (IANA) to regional Internet registries (RIRs) such as the American Registry for Internet Numbers (ARIN), Asia-Pacific Network Information Centre (APNIC), and Réseaux IP Européens Network Coordination Centre (RIPE NCC). RIRs then allocate blocks of IP addresses to Internet service providers (ISPs) and other organizations within their designated regions. ISPs then assign individual IP addresses to their customers through various methods such as dynamic allocation, static allocation, and network address translation (NAT).