What is IP Address?
IP Address (Internet Protocol Address) is a unique numerical identifier assigned to every device connected to a computer network that uses the Internet Protocol for communication. It serves two main functions: host identification and location addressing.
Quick Facts
| Full Name | Internet Protocol Address |
|---|---|
| Created | 1981 (IPv4), 1998 (IPv6) |
| Specification | Official Specification |
How It Works
IP addresses come in two versions: IPv4 and IPv6. IPv4 addresses are 32-bit numbers typically written as four decimal numbers separated by dots (e.g., 192.168.1.1), providing about 4.3 billion unique addresses. Due to address exhaustion, IPv6 was developed with 128-bit addresses written in hexadecimal (e.g., 2001:0db8:85a3::8a2e:0370:7334), providing virtually unlimited addresses. IP addresses can be public (routable on the internet) or private (used within local networks). DHCP typically assigns addresses dynamically, while servers often use static addresses. Due to IPv4 exhaustion, Carrier-Grade NAT (CGNAT) allows ISPs to share single IPv4 addresses among multiple customers, complicating direct connections and geolocation. IPv6 adoption continues to grow, with dual-stack deployment (supporting both IPv4 and IPv6) being the most common transition strategy. NAT64/DNS64 enables IPv6-only clients to access IPv4 resources.
Key Characteristics
- IPv4: 32-bit, ~4.3 billion addresses (e.g., 192.168.1.1)
- IPv6: 128-bit, virtually unlimited addresses
- Can be public (internet) or private (local network)
- Dynamic (DHCP) or static assignment
- Includes network and host portions
- Subnet masks define network boundaries
Common Use Cases
- Device identification on networks
- Routing internet traffic
- Geolocation and content delivery
- Network security and access control
- Server hosting and DNS resolution
Example
Loading code...Frequently Asked Questions
What is the difference between IPv4 and IPv6?
IPv4 uses 32-bit addresses (e.g., 192.168.1.1) providing about 4.3 billion addresses, while IPv6 uses 128-bit addresses (e.g., 2001:db8::1) providing virtually unlimited addresses. IPv6 also includes built-in security features, simplified headers, and eliminates the need for NAT in most cases.
What is the difference between a public and private IP address?
Public IP addresses are globally unique and routable on the internet, assigned by ISPs. Private IP addresses (10.x.x.x, 172.16-31.x.x, 192.168.x.x) are used within local networks and not routable on the internet. NAT (Network Address Translation) allows private addresses to access the internet through a public address.
Why are we running out of IPv4 addresses?
IPv4's 32-bit address space provides only about 4.3 billion addresses, which seemed sufficient when designed in 1981. The explosion of internet-connected devices (computers, phones, IoT devices) has exhausted this pool. IANA allocated the last IPv4 blocks in 2011, driving adoption of IPv6 and widespread use of NAT.
What is DHCP and how does it assign IP addresses?
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to devices on a network. When a device connects, it broadcasts a DHCP discover message. A DHCP server responds with an available IP address, subnet mask, gateway, and DNS servers, leased for a specific time period.
Can two devices have the same IP address?
On the same network, two devices cannot have the same IP address without causing conflicts. However, devices on different private networks can use the same private IP addresses since they're isolated. On the internet, public IP addresses must be globally unique, managed by regional internet registries.