What is IPv6, and How Does It Differ From IPv4?

As the internet continues to expand, the limitations of the existing address space become increasingly transparent. In the early days of the internet, Internet Protocol version 4 (IPv4) seemed sufficient; after all, it boasted 4.3 billion IP addresses. However, it quickly became apparent that the rapid growth of the digital landscape would outpace the number of available addresses. A solution, Internet Protocol version 6 (IPv6), was developed to accommodate the Internet's rapid growth.

‍

Due to compatibility and familiarity, IPv4 persists, but it increasingly faces limitations that IPv6 is designed to overcome. IPv6 not only offers a vast expansion of available addresses, reaching into the trillions, but it  improves efficiency and speed while incorporating modern security features, such as methods for self addressing without the need for Dynamic Host Configuration Protocol (DHCP).

What Is IPv4?

Everything has an address—houses, offices, landmarks—and the internet is no exception. While domain names like dnsmade.easy.com are easy for users to remember, computers communicate differently.

‍

IPv4 allows devices to connect to the internet. It assigns each device a unique address IP address using a 32-bit address scheme. Each IPv4 address is written in a numeric format, consisting of four numbers separated by periods, like 127.0.0.1. Despite its limitations, IPv4 remains fundamental to internet communication, and multiple "life extenders" have been developed to delay the exhaustion of IPv4 addresses.

Why replace IPv4?

IPv4's 32-bit address system has a limited capacity and can't fulfill this new demand. In 2011, the IANA officially ran out of free IPv4 addresses, and by 2020, Europe's regional internet registry had depleted its IPv4 pool. This meant internet service providers (ISPs) and businesses had to recycle or buy IPv4 addresses at inflated secondary prices.

Why is IPv4 still in use?

Change is difficult, even in the rapidly evolving digital landscape. Despite IPv6 being a 30-year-old protocol, both ISPs and businesses remain reluctant to make the switch. A variety of factors have resulted in slow IPv6 adoption: a lack of ISP incentives and concerns about compatibility with existing network devices and systems already configured for IPv4, although many modern devices are built to support both protocols. For the security and IT teams managing the transition, IPv4 is also simply easier to manage. After all, it's easier to remember a numeric address than an alphanumeric or hexadecimal address.

‍

Additionally, the development of Network address translation (NAT) has helped extend the lifespan of IPv4, reducing the urgency of the transition. NAT allows multiple devices in a private network to share a single public IP address, drastically reducing demand.

‍

In the end, while IPv6 offers many benefits, the world is still reliant on IPv4 for everyday internet operations.

What Is IPv6?

IPv6 was designed to go the distance, creating an address space to meet the needs of a vast and growing internet. It also offers a multitude of other benefits:

Larger address pool

IPv6 was designed to ensure we never run out of addresses, and with its near-infinite IP capacity—up to 340 undecillion addresses—there are enough IP addresses for every person on Earth could have billions of trillions of IPv6 addresses. 

‍

IPv4 has a 32-bit address space, which provides about 4.3 billion unique numeric addresses. With the surge of connected devices like mobile phones and laptops, this pool of IP addresses is almost exhausted. IPv6, in contrast, uses a 128-bit alphanumeric address written using a colon-separated hexadecimal notation. Here’s an example IP address using each protocol: 

• IPv4: 192.0.2.0
• IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
• Note: IPv6 also has a shorthand notation, so this address would be simplified to 2001:db8:85a3::8a2e:370:7334 

‍

This means IPv6 can offer a significantly larger address space, ensuring a supply of addresses for the foreseeable future. IPv6 uses hexadecimal digits to create alphanumeric addresses, providing trillions of possible combinations. This eliminates the need to use NAT and solves many compatibility issues found in IPv4.

Speed and efficient routing

IPv6 is not inherently faster than IPv4 in terms of raw speed. However, it improves the efficiency of data transmission. The protocol was designed to streamline routing by removing the need for manual configuration of checksum fields. This makes processing data packets quicker.

‍

Moreover, IPv6 integrates Quality of Service (QoS) features, which prioritize data traffic for important applications. While IPv4 can work on mobile devices, IPv6 is better suited for mobile networks. This means faster and more reliable connections for users, as the network can handle more traffic effectively. IPv6 also supports multicasting, which is more efficient than broadcasting.

Can we use both IPv4 and IPv6?

Despite the differences, both protocols can run concurrently, allowing for seamless transitions in compatibility and support across various network infrastructures. Many modern network devices, including routers and switches, are equipped to handle both protocols. This dual-stack approach means that devices can communicate using either protocol, ensuring that connectivity is maintained across the network. This capability is essential, given the significant number of devices still relying on IPv4.

‍

Running both protocols helps to address compatibility issues during the gradual shift to IPv6. It allows networks to function efficiently while they update their systems to accommodate IPv6. Mobile devices and mobile networks also benefit from this capability, as IPv6 was designed to better support mobile connectivity with its improved address structure and efficient routing capabilities.

‍

In practice, using both IPv4 and IPv6 ensures that no Internet-enabled device is left behind, regardless of the protocol it supports. This dual compatibility ensures ongoing connectivity and makes sure that existing networks remain operational as the world moves toward adopting IPv6 more widely. As more devices continue to connect to the Internet, this ability becomes crucial, allowing for continuous growth without disruptions.

‍

However, while it's possible to use both protocols concurrently, it’s worth noting that modern web browsers prefer IPv6 over IPv4 when both are available, following the Happy Eyeballs (RFC 8305) algorithm.

How IPv4 vs. IPv6 impacts DNS management

Often referred to as "the internet's address book," the Domain Name System (DNS) is how users navigate the internet. The shift from IPv4 to IPv6 brings several important changes to DNS management:

DNS record type: A vs AAAA records

IPv4 and IPv6 use different records; "A" and "AAAA" (also called Quad A) respectively.  You can’t create a AAAA record using an IPv4 address or vice versa. Just like A records, AAAAs can point to the root of your domain or to a subdomain. They can also be used simultaneously. 

Increased complexity in address management

Configuring a DNS server in an IPv6 network can be demanding for network administrators. IPv6 addresses are longer and use hexadecimal notation and shorthand notations that can be confusing to administrators more familiar with IPv4, all of which make manual configuration and troubleshooting more prone to errors. Ensuring compatibility with existing IPv4 infrastructure, managing address resolution, and handling the various IPv6-specific settings require a deep understanding of both IPv4 and IPv6 addressing.

DNS queries and resolution differences

When a device requests a domain name, it may receive both an A (IPv4) and an AAAA (IPv6) record. The device then decides which to use; this is influenced by OS settings and network configurations. Inconsistent configurations may cause latency issues, failed connections, or incorrect resolutions if IPv6 isn’t properly supported.

‍

For example, imagine a user trying to access dnsmadeeasy.com from a network that supports both protocols. Their device, a laptop in this case, sends both an A and AAAA DNS query to resolve the website’s IP address. The website’s hosting provider enabled IPv6, but their web server isn't fully configured to handle IPv6 traffic correctly. The IPv6 address does not respond to requests because the firewall is blocking IPv6 traffic. The result: the user’s browser waits for a response that never comes—causing a delay or apparent downtime.

Transitioning from IPv4 to IPv6

The adoption of IPv6 faces continues to move at a slow and steady pace. Data from Google shows that as of early 2025, global IPv6 adoption stands at slightly below 50%, with the United States lagging behind countries such as France, Germany, and India.

‍

The adoption rate is higher in other countries for numerous reasons. France, in particular, has benefited from mobile network operators increasing IPv6 subscriptions and support from major ISPs. In the United States, ISP hesitancy remains a hurdle for increased adoption. However, government support for the transition has steadily increased over the last several years.

Ready to make the switch?

While IPv4 is still in use, its limitations make IPv6 the inevitable future of networking. As more organizations, governments, and service providers adopt IPv6, users will experience improved security, faster performance, and a more scalable internet.

‍

Interested in making the transition? Click here to learn more about managed DNS services that will simply IPv6 DNS configuration.

‍