What Is an IPv4 Address? Everything You Need to Know
If you've ever tried to troubleshoot your internet connection, set up a home network, or wondered what those four numbers mean when someone says "check your IP address," you're dealing with IPv4 — the addressing system that's been the backbone of internet communication for decades.
The Short Answer: What IPv4 Actually Is
IPv4 stands for Internet Protocol version 4. It's the fourth revision of the Internet Protocol, and it defines how devices on a network identify themselves and communicate with each other.
An IPv4 address looks like this: 192.168.1.1
It's made up of four groups of numbers, each ranging from 0 to 255, separated by dots. This format is called dotted-decimal notation. Behind the scenes, each group represents 8 bits of binary data — making a full IPv4 address 32 bits long.
That 32-bit structure means there are roughly 4.3 billion possible IPv4 addresses in total. That sounds like a lot, but the internet long ago ran out of unallocated ones — which is a big reason why IPv6 exists, but more on that shortly.
What Does an IP Address Actually Do? 🌐
Think of an IP address like a postal address for your device. When you send a request — say, loading a website — your device attaches its IP address to that request so the responding server knows where to send the data back.
Every device connected to a network needs an IP address to communicate. Without one, it can't send or receive data.
There are two distinct types of IPv4 addresses you'll encounter:
Public IP Address
This is the address your internet service provider (ISP) assigns to your router or modem. It's visible to the outside world — websites, servers, and online services see this address when you connect to them. It's how the internet knows where your network is.
Private IP Address
This is the address assigned within your local network — your home or office. Your router acts as a middleman, giving each connected device (phone, laptop, smart TV) its own private IP address. These addresses are never directly visible to the outside internet.
Common private IP ranges include:
10.0.0.0 – 10.255.255.255172.16.0.0 – 172.31.255.255192.168.0.0 – 192.168.255.255
That last range — 192.168.x.x — is the one most people see when they check their home network settings.
How IP Addresses Are Assigned
IPv4 addresses aren't usually set manually (though they can be). Most networks use DHCP — Dynamic Host Configuration Protocol — which automatically assigns an available IP address to each device when it connects.
| Assignment Type | What It Means |
|---|---|
| Dynamic IP | Changes periodically; assigned automatically by DHCP |
| Static IP | Fixed and manually configured; doesn't change |
| Public IP | Assigned by your ISP; faces the internet |
| Private IP | Assigned by your router; local network only |
Static IPs are commonly used for servers, printers, or any device that needs a consistent, predictable address. Dynamic IPs are the standard for most home devices.
NAT: How Billions of Devices Share Limited Addresses
Given that IPv4 only supports ~4.3 billion addresses — and there are far more internet-connected devices than that globally — how does it still work?
The answer is NAT, or Network Address Translation. Your router uses NAT to let multiple devices share a single public IP address. Internally, each device gets a unique private address. Externally, they all appear as one public address. The router keeps track of which internal device made which request and routes the responses accordingly.
NAT has essentially extended IPv4's lifespan well beyond what was originally anticipated — but it comes with trade-offs, including added complexity for hosting services or running certain peer-to-peer applications.
IPv4 vs. IPv6: Why Both Still Exist 🔄
IPv6 was developed to solve IPv4's address exhaustion problem. Instead of 32 bits, IPv6 uses 128 bits — generating an astronomically larger pool of addresses (approximately 340 undecillion).
An IPv6 address looks very different: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Despite IPv6 being available for years, most of the internet still runs on both protocols simultaneously, a setup called dual-stack. Many networks, devices, and ISPs support IPv6, but IPv4 remains deeply embedded in infrastructure.
Whether your connection uses IPv4, IPv6, or both depends on your ISP, your router's configuration, and the services you're connecting to.
What Affects Your IPv4 Setup
Several factors shape how IPv4 works in practice for any given user:
- ISP configuration — whether you get a static or dynamic public IP, and whether IPv6 is supported
- Router model and firmware — affects NAT behavior, DHCP lease times, and network management options
- Operating system — Windows, macOS, Linux, Android, and iOS each have different interfaces for viewing and configuring IP settings
- Network type — home networks, corporate networks, mobile data, and public Wi-Fi all manage IP addressing differently
- Use case — gaming, remote work, self-hosting, or simply browsing each interact with IP addressing in distinct ways
How to Find Your IPv4 Address
The method varies by device and what you're looking for:
- Your public IP: Search "what is my IP" in any browser — your public IPv4 address will appear immediately
- Windows: Run
ipconfigin Command Prompt - macOS/Linux: Run
ifconfigorip addrin Terminal - Router admin panel: Typically accessible at
192.168.1.1or192.168.0.1in a browser
What you see — and what matters — depends entirely on whether you're diagnosing a local network issue, configuring port forwarding, checking what an external server sees, or something else entirely.