IPv4 vs IPv6 – The Internet Protocol Comparison

IPv4 vs IPv6 – The Internet Protocol Comparison

Computers and devices can communicate over the internet because of the Internet Protocol (IP).

Currently, there are two versions of IP – IPv4 and IPv6. Both are used to label devices connected to a network, but they differ in several aspects.

In this article, you’ll learn about the differences between IPv4 vs IPv6 and the future of each internet protocol version.

What Is an Internet Protocol (IP)

IP is a set of rules responsible for routing data across networks and getting them to the right destination.

When sending data across a network, a computer divides the information into bits called data packets, which makes the process of data transfer faster and more efficient.

Each of the data packets contains both the IP address of the source and the destination. An IP address is a unique identifier assigned to all devices connected to the internet or computer network.

In the same way you need a mailing address to send a letter, a device also needs a correct IP address to send information across a network.

Here’s an example of what IP addresses might look like:

IP addresses are distributed by the Internet Assigned Numbers Authority (IANA), an organization in the United States responsible for managing the IP address pool.

Keep in mind that an IP address is different from a domain name, which is a website address that is easier to remember than numerical IP addresses.

What Is IPv4

The Internet Protocol version 4 (IPv4) is the first and most well-known version of the internet protocol. It depends on the best-effort delivery approach, which doesn’t guarantee data delivery or service quality.

This means that users may face delays and other issues depending on the current internet traffic load.

IPv4 is also a connectionless protocol, which transmits data packets without ensuring whether the destination device is ready. The advantage of this type of protocol is that it can send packets through alternate paths in case of network congestion or router failures.

This IP version uses a 32-bit address, the format that most people are familiar with when talking about an IP address. An IPv4 address consists of four decimal numbers, separated by three dots, ranging from 0 to 255, such as:

The 32-bit address space can provide about 4.3 billion addresses. However, some large blocks of these addresses are kept for private networks and unavailable for public use.

What Is IPv6

The Internet Protocol version 6 (IPv6) is the newer version of IP that’s also referred to as the Internet Protocol Next Generation (IPng).

It functions similarly to the Internet Protocol version 4 (IPv4), which provides unique addresses for all devices connected to the internet. However, unlike IPv4, IPv6 uses a 128-bit address instead of the 32-bit address format.

A 128-bit address space offers around 340 undecillion addresses or 1,028 times more addresses than IPv4.

An IPv6 address contains both numbers and letters. It’s written using eight groups of four-digit hexadecimal numbers, separated by colons.

Here’s an example of an IPv6 address:


In addition to more IP addresses, IPv6 also has a simpler header than IPv4. An IP header is the meta-information at the beginning of an IP packet.

IPv6’s header comes with a new format designed to minimize header overhead, making packet processing more efficient.

Another difference between IPv6 vs IPv4 is the latter eliminates the need for Network Address Translation (NAT), restoring the end-to-end connectivity at the IP layer.

It also makes services such as Voice over Internet Protocol (VoIP) and Quality of Service (QoS) easier to implement and deploy.

Why Do We Need Two IP Versions

Even though the maximum number of IPv4 addresses might seem a lot, it’s not enough to accommodate all connected devices worldwide, especially with the rise of the Internet of Things (IoT) devices.

That’s why IPv6 comes to fulfill the need for more internet addresses. However, as the world starts moving towards this protocol, the use of IPv4 is still needed.

While many major content providers such as Facebook and Netflix are now reachable over IPv6, only 19.1% of Alexa’s top ten million websites can be reached over this protocol, showing that there is still a long journey to adopt IPv6 fully.

The Difference Between IPv4 and IPv6

The main difference between IPv4 and IPv6 is their address format and available address space. IPv4 uses a 32-bit address format, allowing for approximately 4.3 billion unique addresses. IPv6, on the other hand, uses a 128-bit address format, allowing for approximately 340 undecillion unique addresses, providing a virtually limitless supply of addresses for future growth.

Additionally, IPv6 includes built-in security features, improved network auto-configuration, and support for more efficient routing, making it a more advanced and secure protocol.

Now that you know some details about the two protocols, it’s time to see the difference between IPv4 vs IPv6. Let’s take a look at the comparison table below.

Size of address 32-bit IP address.128-bit IP address.
Number of header fields12.8.
Length of the header field20 bytes.40 bytes.
Addressing methodIPv4 is based on a numeric address.IPv6 is based on an alphanumeric address.
Type of addressesBroadcast, multicast, and unicast.Anycast, multicast, and unicast.
Checksum fieldsPresent.Absent.
Number of classesFive different classes, from class A to E.Unlimited number of IP addresses.
ConfigurationUsers must configure a newly installed system to make IPv4 communicate with other systems.Configuration is optional and depends on the functions needed.
Virtual length subnet mask (VLSM)  supportIt supports VLSM.It doesn’t support VLSM.
Routing information protocol (RIP)IPv4 is supported by RIPv1 and RIPv2.IPv6 is supported by RIPng.
Network configuration Networks are configured either manually or via dynamic host configuration protocol (DHCP).IPv6 comes with auto-configuration capabilities.
Address featuresIPv4 uses Network Address Translation (NAT), allowing a single NAT address to represent thousands of non-routable addresses.IPv6 supports direct addressing because of its vast space of address.
Address maskIt’s used for the designated network from the host portion.IPv6 doesn’t use an address mask.
Address configurationManually or via DHCP.Stateless address autoconfiguration using the Internet Control Message Protocol version 6 (ICMPv6) or DHCPv6.
Packet size576 bytes of minimum packet size. 1208 bytes of minimum packet size.
Packet fragmentationIt’s done by the sender and forwarding routers.It’s done by only sender routers.
Packet headerIPv4 doesn’t identify packet flow for QoS handling, including checksum options.Flow Label fields specify packet flow for QoS handling.
SNMPSupport included.Not supported.
Mobility and interoperability It uses relatively constrained network topologies, restricting mobility and interoperability capabilities.IPv6 provides mobility and interoperability capabilities included in network devices.
DNS recordsIPv4 features A records.IPv6 features AAAA records.
SecurityIPv4’s security depends on applications.IPv6 has Internet Protocol Security (IPSec) out-of-the-box.
Local subnet group managementIPv4 uses Internet Group Management Protocol (IGMP).IPv6 uses Multicast Listener Discovery (MLD).
MappingIPv4 utilizes Address Resolution Protocol (ARP).IPv6 uses the Neighbor Discovery (ND) process for address resolution.
Mobile device compatibility IPv4 addresses use dot-decimal notation, making them less suitable for mobile networks.IPv6 addresses use hexadecimal and colon-separated notations. That’s why IPv6 is better suited to handle mobile networks.
Dynamic host configuration protocol(DHSP)Users need to approach a DHCP when trying to connect to a network.Users don’t need to contact any servers since they are given permanent addresses.
Optional fieldsPresent.Absent, but it has extension headers instead.

The table shows the many differences between IPv4 and IPv6. For instance, IPv6 supports the anycast mode of packet routing, a widely used model for content delivery network (CDN) products that bring their content closer to the end-user. Meanwhile, IPv4 doesn’t come with this feature by default.

Now, we’re going to dive deeper into comparing IPv6 to IPv4 based on two important aspects: speed and security.

IPv4 vs IPv6 – Security

IPv6 offers more advantages than its predecessor, mainly because it comes with IP Security (IPSec), a group of protocols that secure network communications at the IP layer.

IPSec has three components that secure different aspects of network communications:

  • Authentication Headers (AH) – help the network verify where a packet came from and whether the transmission has been changed. They can also prevent hackers from creating fraudulent data packets to pass malware to a device or application.
  • Encapsulating Security Payloads (ESP) – add encryption and another layer of authentication to protect the data transmission.
  • Internet Security Association and Key Management Protocol (ISAKMP) – defines the security attributes two devices will use to exchange data.

Although IPSec can also be used in IPv4, its usage depends on the network providers and end-users. Also, this framework won’t work in NAT-based communication.

Another security benefit of IPv6 is that it can run end-to-end encryption and integrity-checking, making man-in-the-middle (MitM) attacks more difficult.

IPv6 also uses the Secure Neighbor Discovery (SEND) protocol, resulting in more secure name resolution. This makes it more challenging for attackers to redirect traffic between two legitimate hosts and observe or manipulate the conversation.

IPv6 might bring better security solutions than IPv4, but those security features also depend on the proper design and implementation of IPv6. It’s also essential to activate a firewall, access control system, and antivirus software.

IPv4 vs IPv6 – Speed

The security service provider Sucuri ran a series of tests on sites that support IPv4 and IPv6 and found that both delivered the same speed in direct connections.

However, more evidence suggests that IPv6 is faster than IPv4. One of them is Akamai’s study, which showed performance improvements for IPv6 over IPv4 in the top four US mobile networks.

Akamai's homepage.

Another one is the observation by Facebook’s Engineering, which states that accessing Facebook over IPv6 can be 10-15% faster than using IPv4.

The difference between IPv4 and IPv6 that makes the latter slightly faster is that IPv6 connections access the network directly. Even though IPv4 has smaller packet headers than IPv6, it has to go through stateful NAT servers to travel over the web.

The Future of IPv4

Only a few IPv4 addresses are available nowadays. Even RIPE NCC, one of the Regional Internet Registries (RIRs), has announced that it has run out of IPv4 addresses.

However, IPv4 will still be used on the web in the foreseeable future before we can entirely turn it off. Here are some of the reasons:

  • Replacing IPv4 equipment is expensive. Upgrading software and hardware that were designed to work with IPv4 is costly and time-consuming.
  • Lack of compatibility. Many older devices and systems are still incompatible with IPv6. This might cause some issues, including a DNS error.
  • Many network operators adopt the “wait and see” approach. Since the cost to run both IPv4 and IPv6 or implement dual-stack is high, many network operators choose to remain on IPv4 and wait until more networks switch to IPv6.
  • Usage of NAT. This technology extends IPv4 addresses, as it lets users distribute a single IP address across thousands of devices at a low cost.
  • IPv4 addresses get sold and re-used. Businesses and organizations that need IPv4 addresses can still purchase them through IPv4 address brokers.

Adapting to IPv6

Although it might seem easier to stick with IPv4, deploying this version can also be expensive as the prices of IPv4 addresses are determined by supply and demand.

Also, using NAT as an alternative for IPv6 comes with some drawbacks. One of them is that NAT was developed as a temporary technology, so it might not work well with some applications and protocols.

These problems indicate that IPv6 deployment is the only viable solution for the growth of the internet.

The good news is that the transition to IPv6 has already started. According to Google, the worldwide adoption of IPV6 is currently at 37%.

As more internet service providers (ISPs), mobile carriers, and other large enterprises migrate to IPv6, the number of websites that support IPv6 and users who upgrade their software and equipment for IPv6 are also increasing.

The migration from IPv4 to IPv6 might progress very slowly due to the reasons mentioned earlier, but we can expect a faster deployment in the years to come.

Hostinger and IPv6

To provide the best performance to visitors, customers, or employees with IPv6 devices, users should check with their hosting providers whether their services support IPv6.

If a web hosting provider only supports IPv4 and one of its IP addresses is blackhole (null) routed, clients that share the same IP will be affected.

At Hostinger, VPS hosting users can avoid this problem entirely, as we provide a unique IPv6 address for every website and client on VPS plans.

We also run our internal infrastructure and communication between services using IPv6, trying to push the world to move forward towards full deployment of this new IP.

Hostinger web hosting banner


With the internet protocol, computers and devices can send and receive data over the internet. The two versions of IP that currently exist are IPv4 and IPv6.

There are many differences between IPv4 vs IPv6, and some of the most notable ones are:

  • Number of addresses – IPv4 can provide about 4.3 billion addresses, while IPv6 offers 1,028 times more addresses than its predecessor.
  • Security – IPv6 has more advantages, as it comes with IPSec to secure network communications, and it can run end-to-end encryption to prevent MitM attacks.
  • Speed – IPv6 can access the network without passing through NAT, making it perform faster than IPv4. Studies by Akamai and Facebook also suggest that IPv6 is faster than IPv4.

Since IPv4 can’t accommodate all connected devices worldwide, we need IPv6 addresses to fulfill the need. However, IPv4 will still be deployed in the foreseeable future as many IPv4 addresses get sold and re-used, and many users are still relying on NAT. It might take years or decades until the world can fully adopt IPv6.

To provide an excellent experience for users with IPv6 devices, make sure to choose a web hosting provider that can integrate IPv6 onto your website seamlessly, like Hostinger.

We hope this IPv4 vs IPv6 article has helped you understand the difference between these protocols. If you have any questions, feel free to drop us a comment below.

The author

Amanda B.

Amanda is a WordPress and digital marketing enthusiast with a passion for helping others grow their businesses and careers. She enjoys producing content that is both informative and helpful. When she's not working, Amanda loves hiking, reading books, and filling her bullet journal.