IP Address

An IP address is the numeric identifier assigned to a network interface—32 bits for IPv4 (four decimal octets) and 128 bits for IPv6 (eight hexadecimal groups)—used for network addressing.

Purpose

It gives every interface on the Internet a unique address so packets can be routed to their destination.

Mechanism

IPv4 is 32 bits in dotted-decimal (192.168.1.1), split into network and host parts (determined by the subnet mask). IPv6 is 128 bits in colon-separated hexadecimal (2001:db8::1) with zero compression. Addresses are allocated by IANA and configured via DHCP or SLAAC.

Use cases

Network communication addressing
Firewall rules
Access control lists
Logging and auditing

Examples

Input
```
192.168.1.1
```
Output
```
A private IPv4 address
```
RFC 1918

Common errors

Confusing public and private IP addresses: Memorize the RFC 1918 ranges: 10/8, 172.16/12, and 192.168/16

Related terms

IPv4 is the 32-bit network addressing protocol, written in dotted decimal (e.g., 192.168.1.1), with roughly 4.3 billion addresses—now exhausted.

IPv6 is the 128-bit network addressing protocol, written in colon-separated hexadecimal (e.g., 2001:db8::1), offering about 3.4×10^38 addresses to solve IPv4 exhaustion.

A subnet is a technique for dividing a large network into smaller ones, using the subnet mask to separate the network number from the host number, improving address utilization and isolation.

CIDR (Classless Inter-Domain Routing) expresses a network as IP/prefix length (e.g., 10.0.0.0/8), replacing IPv4 address classes with flexible network partitioning.

A MAC address is the 48-bit hardware address of a network interface card (e.g., 00:1A:2B:3C:4D:5E) that identifies the device at the link layer; the OUI is assigned by IEEE.

Related tools

IP Address Info

Analyze IPv4/IPv6 addresses and CIDR subnets: class, private/multicast flags, binary/hex, reverse DNS, network/broadcast/hosts. Free, private, and 100% client-side.

References