Every time you send an email, stream a video, or load a webpage, your device relies on a fundamental piece of internet infrastructure: the IP address. But what exactly is it—and why do we have two main types: IPv4 and IPv6?
Let’s break it down in plain terms.
The Basics: What Is an IP Address?
An IP (Internet Protocol) address is a unique identifier assigned to any device connected to a network. It allows computers, phones, servers, and smart gadgets to find and communicate with each other over the internet—much like a street address ensures your mail reaches the right house.
Without IP addresses, data packets wouldn’t know where to go. They’re the backbone of online communication.
IPv4: The Original Standard
Launched in 1983 on the ARPANET (the precursor to today’s internet), IPv4 uses a 32-bit numbering system. This format produces about 4.3 billion possible addresses—a number that once seemed more than enough.
IPv4 addresses are written as four decimal numbers between 0 and 255, separated by dots:
Example: 192.168.1.1 or 214.198.7.2
For decades, IPv4 powered the entire internet. Every website, router, and smartphone used it—and most still do today, thanks to compatibility layers and workarounds like NAT (Network Address Translation).
But as the digital world exploded, one problem became unavoidable: we ran out of IPv4 addresses.
IPv6: The Next-Generation Solution
To solve the address shortage, engineers developed IPv6, which uses 128 bits—a massive leap from IPv4’s 32. The number of possible IPv6 addresses is so large (roughly 340 undecillion) that it could assign millions of unique IPs to every grain of sand on Earth.
IPv6 addresses are written in hexadecimal, grouped into eight blocks of four characters, separated by colons:
Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
To keep things readable, leading zeros in each block can be omitted, and one continuous string of zero blocks can be replaced with :::
Shortened: 2001:db8:85a3::8a2e:370:7334
IPv6 also supports dual-stack formats for backward compatibility. For instance:::ffff:192.1.56.10 — this lets IPv6 systems interact with older IPv4-only services.
Who Assigns IP Addresses?
IP addresses aren’t random—they’re carefully managed:
- ICANN (Internet Corporation for Assigned Names and Numbers) oversees the global pool.
- It delegates large blocks to five Regional Internet Registries (RIRs):
- ARIN – North America
- RIPE NCC – Europe, Central Asia, Middle East
- APNIC – Asia-Pacific
- LACNIC – Latin America & Caribbean
- AfriNIC – Africa
These RIRs then allocate addresses to local internet registries (LIRs)—mostly internet service providers (ISPs)—who assign them to end users.
If you’re on a home network, your ISP gives you a public IP. If you’re on a private network (like your Wi-Fi), your router assigns local IPs (e.g., 192.168.x.x or 10.x.x.x) using reserved ranges that aren’t visible on the public internet.
How IP Addresses Are Structured
Historically, IPv4 addresses were divided into classes (A, B, C, etc.), based on the first few bits. These determined how many bits were used for the network portion vs. the host (device) portion.
While classful addressing is mostly obsolete today, replaced by CIDR (Classless Inter-Domain Routing), the concept still matters for understanding subnetting and routing.
Static vs. Dynamic IPs: What’s the Difference?
- Static IP: Fixed and permanent. Often used by servers, businesses, or services that need consistent access (like remote security cameras or hosting websites).
- Dynamic IP: Temporarily assigned by your ISP or router via DHCP (Dynamic Host Configuration Protocol). It changes periodically—typically when you reboot your modem or reconnect to the network.
Most home users get dynamic IPs by default. It’s efficient, cost-effective, and sufficient for everyday browsing, streaming, or social media.
💡 Fun fact: Even with a dynamic IP, your ISP keeps logs linking that address to your account at any given time—important for legal or security investigations.
One Device, Multiple IPs?
Yes! A single machine can have multiple IP addresses if it’s connected to several networks (e.g., Wi-Fi + Ethernet) or running virtual machines. Routers, in particular, have one IP per interface—one for your local network, another for the public internet.
Crucially, an IP address belongs to a network interface, not the physical device itself.
Final Thoughts
IP addresses may seem technical, but they’re essential to how the internet works. While IPv4 still handles much of today’s traffic, IPv6 is the future—offering near-limitless addresses, better security, and more efficient routing.
As more devices come online—from smart fridges to city traffic systems—the shift to IPv6 isn’t just smart… it’s inevitable.
So next time you load a webpage, remember: somewhere in that magic, there’s an IP address making it all possible.