IPv4 vs IPv6: What's the Difference?
The internet is outgrowing its old addresses. Here's what you need to know about the transition.
Why Two Versions?
IPv4 was designed in the 1980s when no one could imagine billions of devices connecting to the internet. With "only" 4.3 billion possible addresses, the world began running out as early as 2011. IPv6 was developed as the solution to this problem.
Comparison
| Property | IPv4 | IPv6 |
|---|---|---|
| Address length | 32 bits | 128 bits |
| Format | 192.168.1.1 | 2001:db8::1 |
| Number of addresses | ~4.3 billion | ~340 undecillion |
| NAT required? | Yes, usually | No |
| IPSec | Optional | Built-in |
| Status | Still dominant | Growing adoption |
Benefits of IPv6
Vast address space
IPv6 has enough addresses for every single device on Earth to have its own unique, public address — without needing NAT (Network Address Translation).
Better security
IPSec (encryption and authentication) is built into the IPv6 standard, which makes end-to-end encryption easier to implement.
Simpler network setup
IPv6 supports autoconfiguration (SLAAC), allowing devices to configure themselves on the network without a DHCP server.
Faster routing
IPv6 packet headers are simpler than IPv4, making it faster for routers to process and forward traffic.
Dual-Stack: The Bridge Between IPv4 and IPv6
Since the internet can't be switched over all at once, dual-stack is used — devices and networks that support both IPv4 and IPv6 simultaneously. Your computer can then communicate with websites that only have IPv4, and with those that have IPv6.
When IPv4 and IPv6 can't talk directly, transition mechanisms are used. Tunneling wraps IPv6 traffic inside IPv4 packets so it can be sent over older networks. Translation (NAT64/DNS64) translates between the two protocols, so an IPv6-only client can reach IPv4-only servers. These solutions make the transition gradual without cutting anyone off.
IPv6 Adoption Worldwide
Major internet providers around the world have implemented IPv6 support. Many subscribers already have access without knowing it — the router and operating system handle it automatically when the ISP offers it.
The public sector and enterprises have been slower. Migration requires upgrading network equipment, firewalls, and monitoring systems. Many legacy systems still only support IPv4, which creates challenges for large organizations with complex infrastructure. Still, adoption increases year by year.
Migrating to IPv6: Challenges
The transition to IPv6 is slow for several reasons. Legacy systems — from industrial equipment to medical devices — are often designed for IPv4 only and can't be easily upgraded. Cost is a factor: new equipment, testing, and training cost money.
Expertise is also a barrier. Many network administrators are most comfortable with IPv4, and IPv6 requires a new way of thinking — addresses are longer, the notation is different, and troubleshooting becomes more complex. Finally: "if it works, don't touch it" — companies often postpone migration until they absolutely have to.
IPv6 and Security
IPv6 has built-in support for IPSec, making encryption and authentication easier to implement. End-to-end encryption without NAT traversal becomes more natural. At the same time, IPv6 introduces new security considerations.
The huge address space makes traditional IP scanning difficult for attackers, but also for security tools that need to monitor the network. Many firewalls and intrusion detection systems were originally designed for IPv4 and need updating. As with anything new: IPv6 offers opportunities, but requires security work to keep pace.
How Far Have We Come?
According to Google, roughly 45% of global internet traffic uses IPv6 as of 2025. Adoption varies by region, but major internet providers now offer IPv6 support.
Most modern operating systems (Windows, macOS, Linux, iOS, Android) have had full IPv6 support for many years. The challenge lies mainly with legacy network equipment and enterprise networks that need upgrading.
Do You Have IPv6?
You can easily check whether you're using IPv4 or IPv6 by visiting our homepage. If it shows an address with a colon (:), you have IPv6. If it shows four numbers separated by dots, you're using IPv4.
What Should You Do?
As an ordinary internet user, you don't need to do anything special. The transition to IPv6 is handled by your internet provider and your operating system. But it can be useful to know that you're connected to the future of the internet when you see an IPv6 address.