In 1983, when the engineers of the ARPANET project defined the IPv4 standard, it seemed impossible that billions of devices could connect to the internet. The available addresses numbered about 4.3 billion — an enormous figure for the time. Today, with smartphones, PCs, smart TVs, cameras, refrigerators, and thermostats all connected, those addresses are practically exhausted. IPv6 is the answer to this problem, but it brings much more than a simple expansion of the address space.

The Problem with IPv4

IPv4 uses 32-bit addresses, organized into four groups of numbers separated by dots: 93.41.12.204. The maximum number of unique addresses is 2³² = approximately 4.3 billion.

That sounds like a lot, but it isn't. China alone has 1.4 billion inhabitants. Add India, the rest of Asia, Africa with its rapidly growing digital adoption, and the billions of IoT devices coming online every year — it is clear that 4.3 billion is not enough.

The temporary solution adopted in the 1990s is NAT (Network Address Translation): the home router takes a single public IP assigned by the ISP and shares it among all devices on the network, assigning internal "private" addresses (like 192.168.1.x). It works, but it is a patch, not a solution. NAT introduces complexity, slows some connections, and makes it difficult to host services from a home network.

What Is IPv6?

IPv6 uses 128-bit addresses, written in hexadecimal and separated by colons:

2001:0db8:85a3:0000:0000:8a2e:0370:7334

It can be abbreviated by removing leading zeros and groups of all zeros with :::

2001:db8:85a3::8a2e:370:7334

How many addresses does it offer? 2¹²⁸ = approximately 340 undecillion (340 followed by 36 zeros). It is so vast that one could assign a unique IPv6 address to every grain of sand on Earth, billions of times over.

The Main Differences Between IPv4 and IPv6

Address Space

The fundamental difference, already described: IPv4 has ~4.3 billion addresses, IPv6 has enough to never run out.

Header Structure

The IPv6 packet header has been simplified compared to IPv4, despite the address being longer. Fewer fields to process means faster, more efficient routers. The fragmentation functionality (which in IPv4 was in the packet itself) has been moved to end devices, reducing the load on intermediate infrastructure.

Autoconfiguration (SLAAC)

IPv6 includes Stateless Address Autoconfiguration (SLAAC): a device can autonomously generate its own global IPv6 address from the network prefix announced by the router, without the need for a DHCP server. The router announces the prefix via Router Advertisements; the device completes the address with a local identifier.

This greatly simplifies network management, especially in IoT networks where you have hundreds of devices to configure.

Built-in Security

IPv6 was designed with IPsec as a native part of the protocol (in IPv4 it is optional and added later). IPsec handles authentication and encryption of communications at the network layer. In practice, many implementations don't use it by default today, but the architecture is ready for it.

No NAT Required

With IPv6 every device can have its own unique global public address. NAT becomes unnecessary. This is a major advantage for:

• Gaming and P2P applications (direct connections between devices without going through NAT traversal)
• Hosting services from home
• IoT (every sensor is directly addressable)

Multicast Instead of Broadcast

IPv4 uses broadcast to send messages to all devices on a network (e.g., in ARP requests). IPv6 eliminates broadcast and uses multicast more efficiently, reducing unnecessary traffic on large networks.

Where Does the Transition Stand in Italy?

The transition from IPv4 to IPv6 is slow but inexorable. In Italy, according to RIPE NCC and Google IPv6 Statistics data:

• The majority of consumer ISPs (TIM, Fastweb, Vodafone, Iliad) have already enabled IPv6 for fiber contracts, often in dual-stack mode (both IPv4 and IPv6 active at the same time)
• Major sites (Google, Facebook, YouTube, Netflix) have supported IPv6 for years
• The slowest part is the corporate network: many firewalls, corporate VPNs, and older-generation equipment still do not support IPv6

You can check whether your connection uses IPv6 with our My IP tool, which shows both the IPv4 and IPv6 address if available.

Dual-Stack: How the Two Protocols Coexist

Most networks today operate in dual-stack mode: each device has both an IPv4 and an IPv6 address. When a site supports IPv6, the browser preferentially connects via IPv6 (thanks to the Happy Eyeballs mechanism that tries both in parallel). If IPv6 is not available, it automatically falls back to IPv4.

This gradual approach allows the transition without breaking anything.

Want to Run a Ping on IPv6?

If you want to test IPv6 connectivity to a specific domain, you can use our Online Ping tool, which supports both IPv4 and IPv6 and shows latency, packet loss, and connection details.

Frequently Asked Questions

Is IPv6 faster than IPv4? Not necessarily faster in an absolute sense, but it can be slightly more efficient on modern networks thanks to the simplified header and the absence of NAT. Actual latency depends primarily on the physical distance from servers.

Do I need to do anything to enable IPv6? In most cases, no. If your ISP supports IPv6 and your router is modern, enabling is automatic. You can verify this at My IP.

Is IPv6 as secure as IPv4? Yes. Vulnerabilities do not depend on the version of the IP protocol but on how the network is configured and the services exposed. In fact, the absence of NAT in IPv6 requires paying closer attention to the router's firewall, which becomes the only barrier between local network devices and the internet.