IPv4 vs. IPv6: Key Differences, Why It Matters & How It Affects Proxies

Why “What Is the Difference Between IPv4 and IPv6?” Matters to You

You’ve probably seen “IPv4” and “IPv6” pop up when setting up your router, troubleshooting internet issues, or choosing a proxy service—but have you ever stopped to ask: What is the difference between IPv4 and IPv6? And why does it matter for your daily online activities?

Here’s the short answer: IPv4 and IPv6 are both “internet protocol addresses”—unique codes that identify your device on the internet (like a digital home address). The big difference? IPv4 is old, running out of addresses, while IPv6 is its modern replacement with endless addresses. But the nuances go deeper than that—and understanding them can help you avoid network headaches, choose better proxy services, and future-proof your online setup.

This guide breaks down “what is the difference between IPv4 and IPv6?” in simple, jargon-free terms. We’ll start with basic definitions (no tech degree required), then use a detailed comparison table to highlight key differences. We’ll also cover why the switch from IPv4 to IPv6 is happening, and how it impacts proxy services—with a focus on IPFLY, a high-availability proxy that supports both IPv4 and IPv6 (no client required) and outperforms competitors in dual-stack compatibility. By the end, you’ll not only know the differences but also how to apply that knowledge to your online activities.

What Are IPv4 and IPv6, Exactly?

Before diving into differences, let’s clarify what each is—using a simple analogy: The internet is a giant neighborhood, and every device (phone, laptop, router) is a house. An IP address is the unique street address of that house, so data (like emails, videos, or website requests) can find its way to the right place.

What Is IPv4?

IPv4 (Internet Protocol Version 4) is the “original” IP address system, created in the 1980s. It uses a 32-bit format, which looks like this: 192.168.1.1. It’s made of four sets of numbers (0-255) separated by dots—hence the nickname “dot-decimal notation.”

The problem with IPv4? It can only generate about 4.3 billion unique addresses. Back in the 80s, that seemed like more than enough—but with billions of devices (smartphones, IoT devices, smart TVs) now connected to the internet, IPv4 addresses are almost exhausted. To cope, networks use “NAT” (Network Address Translation) to share one IPv4 address across multiple devices—but this causes compatibility issues and slows down certain internet activities.

What Is IPv6?

IPv6 (Internet Protocol Version 6) is the modern replacement for IPv4, designed to solve the address shortage. It uses a 128-bit format, which looks like this: 2001:0db8:85a3:0000:0000:8a2e:0370:7334. It’s made of eight sets of hexadecimal numbers (0-9, A-F) separated by colons—nicknamed “colon-hexadecimal notation.”

The biggest win with IPv6? It can generate 340 undecillion unique addresses (that’s 340 followed by 36 zeros)—more than enough for every device on Earth (and even future devices like smart cars, wearables, and space-based IoT tools). It also fixes many of IPv4’s flaws, like better security and faster data transfer.

What Is the Difference Between IPv4 and IPv6? Key Differences (Table)

To make it easy to compare, here’s a detailed table of the core differences between IPv4 and IPv6:

Why Does the IPv4 vs. IPv6 Difference Matter for Proxy Services?

Now that you know “what is the difference between IPv4 and IPv6?”, let’s talk about a practical use case: proxy services. A proxy’s job is to route your internet traffic through a different IP address—but whether that IP is IPv4 or IPv6 has a big impact on your experience. Here’s why:

Compatibility with Target Websites: Some modern websites (e.g., government sites, global e-commerce platforms) now prioritize IPv6. If your proxy only supports IPv4, you might face access issues or slow speeds.

Address Availability: IPv4 proxies often use shared addresses (due to IPv4 shortage), which are more likely to be blacklisted by websites. IPv6 proxies have unique addresses, reducing blacklist risks.

Speed & Security: IPv6 proxies are faster (no NAT delays) and more secure (built-in encryption) than IPv4 proxies—critical for tasks like web scraping, streaming, or secure browsing.

The best proxy services today support both IPv4 and IPv6 (called “dual-stack” support), so you can switch based on your needs. This is where IPFLY stands out—its high-availability proxy service is optimized for both IPv4 and IPv6, with no client required for setup.

IPFLY: Dual-Stack Proxies for IPv4/IPv6 Excellence (vs. Competitors)

When choosing a proxy service, the difference between IPv4 and IPv6 support can make or break your experience. IPFLY’s dual-stack design (supports both IP versions) and high availability make it a top choice—especially for users who need to switch between legacy IPv4 systems and modern IPv6 networks. Below is how IPFLY compares to competitors in terms of IPv4/IPv6 support and core proxy metrics:

For users who understand the difference between IPv4 and IPv6, IPFLY’s dual-stack advantage is clear: It lets you use the right IP version for the job—IPv4 for legacy websites, IPv6 for modern, fast, secure access—without the hassle of switching proxy services. Its client-free design means you can configure both IPv4 and IPv6 proxies via simple IP:Port settings, making it accessible for beginners and powerful for professionals.

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Example: Configure IPFLY IPv4/IPv6 Proxies (Simple Setup)

Setting up IPFLY’s dual-stack proxies is easy—no client required. Here’s how to use them in a terminal or script (replace placeholders with your IPFLY details):

# Use IPFLY IPv4 proxy (HTTP)
curl --proxy http://[IPFLY_IPv4]:[PORT] --proxy-user [USERNAME]:[PASSWORD] https://example.com

# Use IPFLY IPv6 proxy (HTTPS)
curl --proxy https://[IPFLY_IPv6]:[PORT] --proxy-insecure --proxy-user [USERNAME]:[PASSWORD] https://example.com

How to Check If Your Device Uses IPv4 or IPv6 (Code Snippets)

Curious if your device is using IPv4, IPv6, or both? Use these simple code snippets or commands to check:

Method 1: Terminal/Command Prompt (Windows/Mac/Linux)

# Check IPv4 address
curl https://api.ipify.org?format=json

# Check IPv6 address (only works if your device supports IPv6)
curl https://api6.ipify.org?format=json

If the second command returns an IP address (starts with numbers and colons), your device supports IPv6. If it times out, you’re on IPv4 only.

Method 2: Python Script (Cross-Platform)

import socket

def check_ip_versions():
    # Check IPv4 support
    try:
        socket.create_connection(("api.ipify.org", 443), timeout=5)
        print("IPv4 is supported on your device.")
    except Exception:
        print("IPv4 is NOT supported on your device.")
    
    # Check IPv6 support
    try:
        socket.create_connection(("api6.ipify.org", 443), timeout=5, family=socket.AF_INET6)
        print("IPv6 is supported on your device.")
    except Exception:
        print("IPv6 is NOT supported on your device.")

if __name__ == "__main__":
    check_ip_versions()

Mastering the Difference Between IPv4 and IPv6

We started with “what is the difference between IPv4 and IPv6?” and ended with practical ways to apply that knowledge—from choosing the right proxy service to checking your device’s IP support. To recap the key takeaways:

IPv4 is old, limited in addresses, and relies on NAT—great for legacy systems but aging.

IPv6 is modern, has unlimited addresses, and is faster/secure—ideal for modern devices and global networks.

For proxy services, dual-stack support (IPv4 + IPv6) is critical for compatibility, speed, and security—IPFLY excels here with 99.9% uptime, unique addresses, and client-free setup.

You don’t need to be a tech expert to benefit from understanding IPv4 vs. IPv6. Whether you’re browsing the web, using proxies for work, or setting up a home network, this knowledge will help you avoid issues and get the best possible online experience.

Ready to experience the advantages of dual-stack proxies? Try IPFLY’s IPv4/IPv6 proxies—no client required, just fast, secure, and reliable access to any website, anywhere in the world.