Internet Protocol Guide

What Is an IP Address?

Internet Protocol Explained — Every device needs an IP address to connect. Use our ISP lookup tool to discover who is my ISP.

Check Your IP Address

An IP address — short for Internet Protocol address — is a unique numerical identifier assigned to every device connected to the internet or a local network.

It allows computers, smartphones, routers, and servers to communicate with one another using standardized network protocols defined by the Internet Engineering Task Force (IETF).

Think of it as your device's digital street address — required for sending and receiving any data online. To check your current IP and network identity, visit Who is my ISP.

Core Entities and Concepts

  • Internet Protocol (IP): The foundational networking protocol of the internet.
  • IANA (Internet Assigned Numbers Authority): The global coordinator for IP address allocation.
  • Regional Internet Registries (RIRs): ARIN (North America), RIPE NCC (Europe, Middle East), APNIC (Asia & Pacific), LACNIC (Latin America), AFRINIC (Africa)
  • DNS (Domain Name System): Translates domain names into IPs.
  • ISP (Internet Service Provider): Allocates IPs to end users.

These entities form the hierarchical structure that governs how IP addresses are distributed and used globally.

Types of IP Addresses

IP addresses come in several forms, depending on version, function, and visibility.

1. IPv4 (Internet Protocol Version 4)

  • Format: 32-bit numeric value (e.g., 192.168.1.1)
  • Total Possible Addresses: 4,294,967,296 (~4.3 billion)
  • Structure: Four octets separated by dots (A.B.C.D)
  • Status: Nearly exhausted — primary reason IPv6 was created
  • Entities: ICANN, IANA, IPv4 exhaustion, subnetting

2. IPv6 (Internet Protocol Version 6)

  • Format: 128-bit hexadecimal (e.g., 2400:cb00:2048:1::c629:d7a2)
  • Total Possible Addresses: 2¹²⁸ ≈ 3.4 × 10³⁸
  • Features:
    • Auto-configuration (SLAAC)
    • Built-in security (IPsec)
    • No need for NAT (Network Address Translation)
  • Entities: IETF RFC 8200, dual-stack implementation, ICMPv6

3. Public vs Private IPs

Type Visibility Example Range Usage
Public IP Visible on the internet 8.8.8.8 Assigned by ISP; identifies you globally
Private IP Internal network only 192.168.x.x Used for LAN, routers, IoT devices

Entity: RFC 1918 (Private Address Space)

4. Static vs Dynamic IPs

Static IP

Permanently assigned; ideal for servers, hosting, and VPN endpoints.

Dynamic IP

Temporarily leased via DHCP from the ISP and changes over time.

Entities: DHCP, DNS mapping, reverse DNS (PTR records)

Total IP Address Count and Distribution

Protocol Bit Length Total Addresses Usable Addresses
IPv4 32-bit 4,294,967,296 ~3.7 billion (after reserved)
IPv6 128-bit 3.4 × 10³⁸ Effectively unlimited

Reserved IPv4 Ranges:

  • 10.0.0.0/8 → Private LANs
  • 172.16.0.0/12 → Private networks
  • 192.168.0.0/16 → Home routers
  • 127.0.0.1 → Localhost (loopback)
  • 224.0.0.0/4 → Multicast networks

Entities: Subnet mask, CIDR notation, address blocks

IP Address Blocks and Allocation

IP addresses are organized into CIDR blocks (Classless Inter-Domain Routing) — ranges that group multiple IPs efficiently.

Class Prefix Range Block Size Common Use
Class A 1.0.0.0 – 126.0.0.0 16 million IPs Large networks / ISPs
Class B 128.0.0.0 – 191.255.0.0 65,000 IPs Medium enterprises
Class C 192.0.0.0 – 223.255.255.0 254 IPs Small networks
Class D 224.0.0.0 – 239.255.255.255 Multicast Streaming, routing
Class E 240.0.0.0 – 255.255.255.255 Experimental Reserved by IETF

Entity: CIDR, subnet mask, Class A/B/C structure, multicast

Most Important IP Providers and Organizations

Global Coordinators

  • IANA – Oversees global IP distribution
  • ICANN – Coordinates DNS and IP resources
  • RIRs – ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC

Major ISPs / Carriers

  • AT&T (AS7018)
  • Verizon (AS701)
  • Comcast (AS7922)
  • Cloudflare (AS13335)
  • Google (AS15169)
  • Amazon AWS (AS16509)

Entities: Autonomous System (AS), ASN registry, peering, IP ownership

The Global Shortage of IPv4 Addresses

By 2019, all five RIRs had officially exhausted their IPv4 allocations. This shortage led to:

  • The IPv4 secondary market (buying/selling IP ranges)
  • Massive adoption of NAT (Network Address Translation)
  • Acceleration of IPv6 deployment

Entities: IPv4 scarcity, IP leasing market, CGNAT (Carrier-Grade NAT), IPv6 transition

Transition to IPv6

Why it matters:

  • Virtually unlimited address space
  • Improved routing efficiency
  • Native IPsec encryption
  • Essential for IoT (Internet of Things) scalability

Global IPv6 Adoption (2025):

  • Worldwide average: ~47%
  • USA: ~51%
  • India: ~70%
  • Germany: ~64%

Google, Facebook, and Cloudflare all natively support IPv6

Entities: Dual-stack networks, ICMPv6, SLAAC, IPv6 Prefix Delegation

IP Addresses and Privacy

Your public IP can reveal:

  • ISP name
  • Approximate city or country
  • Network type (mobile, broadband, VPN)

That's why many users use:

  • VPNs (Virtual Private Networks)
  • Proxies
  • Tor Network

to mask their IP and maintain online anonymity.

To check your IP and ISP identity, use Who is my ISP.

Frequently Asked Questions

Find answers to common questions about IP addresses

An IP address is used to identify and communicate with devices on the internet. It ensures data sent from one computer reaches the correct destination using TCP/IP protocols.

IPv4 has 4.29 billion addresses, while IPv6 has 3.4 × 10³⁸ addresses (virtually infinite). IPv6 was created to replace IPv4 due to address exhaustion.

IP addresses are owned and managed by Regional Internet Registries (RIRs) under the global authority of IANA and ICANN. Organizations and ISPs lease address blocks from these registries.

When IPv4 runs out, ISPs reuse existing addresses via NAT or migrate networks to IPv6. IPv6 adoption ensures future scalability for billions of devices.

Not on the same network. Each device must have a unique IP. However, thousands of devices may share one public IP through NAT (e.g., in home routers or ISPs).

Ready to Check Your IP Address?

An IP address is the backbone of all internet communication — a digital identifier connecting every website, phone, and server on Earth. From the early IPv4 era to the new IPv6 revolution, IPs remain the currency of connectivity.

Check Your IP Address & ISP