🌍 Who Manages Public IP Addresses?
The Internet Assigned Numbers Authority (IANA) manages the global pool of public IP addresses and delegates them to Regional Internet Registries (RIRs).
🌍 Regional Internet Registries (RIRs)
IANA distributes IPs to five Regional Internet Registries, each responsible for different parts of the world:
| RIR | Region | Website |
|---|---|---|
| ARIN | North America | https://www.arin.net |
| RIPE NCC | Europe, Middle East, Central Asia | https://www.ripe.net |
| APNIC | Asia-Pacific | https://www.apnic.net |
| LACNIC | Latin America & Caribbean | https://www.lacnic.net |
| AFRINIC | Africa | https://www.afrinic.net |
These RIRs allocate IPs to ISPs, Cloud Providers, Enterprises.
🌍 Who Uses Public IPs?
🔹 Internet Service Providers (ISPs) – Assign public IPs to homes, offices, and mobile networks.
🔹 Cloud Providers (AWS, Google, Azure) – Offer public IPs (Elastic IPs, Floating IPs).
🔹 Enterprises & Governments – Own dedicated IP ranges for their infrastructure.
🌍 How to Check a Public IP Owner?
👉 https://whois.arin.net (ARIN) 👉 https://who.is
Tool Shows which RIR or ISP owns the IP + contact details.
🌍 Difference Between Public and Private IP Addresses
| Feature | Public IP Address 🌍 | Private IP Address 🔒 |
|---|---|---|
| Definition | Assigned by ISPs and routable on the internet | Used within private networks (not routable on the internet) |
| IP Range | Comes from IANA-assigned public IP pools | Uses RFC 1918 ranges standard: 🔹 10.0.0.0/8 🔹 172.16.0.0/12 🔹 192.168.0.0/16 |
| Uniqueness | Globally unique (no two devices can have the same public IP) | Can be reused across multiple private networks |
| Internet Access | Directly accessible from the internet | Requires NAT (Network Address Translation) to access the internet |
| Example Usage | Websites, cloud servers, gaming servers | Home WiFi, corporate LAN, AWS VPCs, internal databases. A home WiFi router assigns 192.168.1.10 to your laptop (private IP). |
| Security | Less secure (exposed to cyber threats) | More secure (not directly reachable from the internet) |
| Cost | Assigned & controlled by ISPs/cloud providers (can be paid) | Free to use within private networks |
| AWS Example | Elastic IP (EIP), EC2 Public IP | AWS VPC subnets, EC2 private IPs |
Key Takeaways
Tip
✅ RFC 1918 IPs are private and can’t be used for public-facing services. ✅ Public IPs are globally unique and assigned by ISPs or cloud providers. ✅ NAT allows private IPs to access the internet by mapping them to a public IP.