IPv4 vs IPv6 Comparison: Differences and Similarities 

Discover key differences between IPv4 and IPv6, including address spaces and security enhancements, in this detailed comparison guide.
12 min read
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In this IPv4 vs IPv6 comparison article, you will see:

  • The definition of IP
  • What IPv4 is
  • What IPv6 is
  • What IPv4 and IPv6 have in common
  • Why we came to IPv6
  • The benefits of IPv6 over IPv4
  • Why IPv6 is still not fully adopted

Let’s dive in!

What Is the Internet Protocol (IP)?

Internet Protocol, simply known as IP, is a communication protocol at the heart of the Internet that enables the transfer of data packets across networks. It specifies a set of rules that dictate how data packets should be addressed, routed, and transmitted between devices on a network. In short, IP helps a packet move from the source device (sender) to the destination device (receiver) across one or more networks.

When a computer tries to transmit information over a network, it breaks down the data into smaller units called packets. These packets are the basic carriers of information. To ensure that they are delivered to the right destination, each packet contains IP-related information.

Every device connected to a network has a unique numeric label, known as an IP address. This uniquely identifies one device from all others on the network. The IP protocol successfully manages to route packets from one device to another up to the destination by using IP addresses.

If you want to find out your public IP, visit sites such as What’s My IP Address. These tools will show you your IP address and a rough estimate of your location (unless you are protecting your IP behind a proxy server).

As you are about to learn as we go through the IPv4 vs IPv6 comparison, there are different versions of IP that you need to be aware of.

What Is IPv4?

IPv4, short for Internet Protocol version 4, represents the fourth version of the Internet Protocol. Despite its sequential numbering, IPv4 IPs were the first version of IP to be implemented and used in a large-scale network, in 1982.

To this day, IPv4 remains the most widely recognized and adopted version of IP for identifying devices within a network. Its longevity and prevalence are due to its effectiveness and widespread adoption over several decades of Internet development.

This is what a sample IPv4 address looks like:

As you can see, an IPv4 address consists of a series of four numbers, each ranging from 0 to 255, separated by periods. Each of these numbers represents an octet, or 8 bits, for a total of 32 bits for the entire address. This 32-bit binary sequence serves as a unique identifier for devices connected to a network.

If you want to learn more about how IPv4 works, check out the dedicated guide What Is IPv4?

What Is IPv6?

IPv6, which stands for Internet Protocol version 6, is the latest iteration of the Internet Protocol. Like its predecessor, IPv6 is a way of identifying and routing traffic among computers on networks.

Developed by the Internet Engineering Task Force (IETF), IPv6 was conceived to replace IPv4. In particular, IPv6 emerged as a response to some of the main challenges and limitations associated with IPv4. In December 1998, IPv6 achieved the status of a Draft Standard within the IETF, but it was only in 2017 that it reached the status of Internet Standard.

Here is a sample IPv6 address:


As you can tell, an IPv6 address consists of a series of eight 16-bit hexadecimal values separated by colons. This format allows for a total of 128 bits, considerably larger than the 32-bit format of IPv4 addresses.

To find out more details about IPv6, check out the complete article What Is IPv6?

Similarities Between IPv4 and IPv6

IPv4 and IPv6 are different versions of the same protocol. As such, they share the following key aspects:

  • Both are used to uniquely identify devices connected to a network.
  • Both are used for routing data packets across networks.
  • Both IP addresses consist of binary numbers.
  • Both support manual address assignment.
  • Both come with error checking and packet fragmentation mechanisms to ensure reliable data transmission.
  • Both have broadcasting and multicasting capabilities.
  • Both support VLSM (Variable Length Subnet Mask).

Keep also in mind that IPv4 and IPv6 can coexist within the same network infrastructure. That is possible through mechanisms such as dual-stack implementations and tunneling protocols.

Why a New Version of IP?

Now you know that IPV4 and IPv6 are two protocols that share the same end goal. Considering that IPv4 is used by millions of devices, you might wonder why we even need a new version of IP. In other words, what is the reason for IPv6? Before digging into the Ipv4 vs IPv6 comparison, we must find an answer to that question.

The main reason behind defining a new standard to replace IPv4 is address exhaustion. The 32-bit IPv4 address space provides about 4.3 (2^32) billion unique addresses. This may seem like a very large number but with the exponential growth of devices connected to the Internet, that address space has been depleted. On the other hand, IPv6 has an address space of 128 bits. This means 2^128, or about 3.4*10^38 total addresses, which means virtually unlimited availability of unique addresses.

IPv6 is a refined version of IPv4, built on several lessons learned. In general, IPv6 was designed as a forward-looking solution that could support emerging network technologies and paradigms. This includes the Internet of Things (IoT), 5G networks, and cloud computing. Its robust addressing scheme, increased routing efficiency, and built-in security features make it suitable for the diverse requirements of modern digital ecosystems.

So, IPv4 or IPv6? See why IPv6 might be better!

Benefits of IPv6 Over IPv4

In addition to the fundamental benefit of solving the IPv4 address shortage, IPv6 comes with some key improvements. Explore them all!

No Geographical Limitations

When IPv4 was created, 50% of all addresses were reserved for the United States. IPv6 addressed that problem and its address spaces will be available to everyone, without favoring any specific region of the world.

End-to-End Connectivity

To overcome the limited address space of IPv4, IPv6 relies on the NAT (Network Address Translation) technology. This system allows multiple devices within a private network to share a single public IP address for Internet access.

The IPv6 wider address space eliminates the need for NAT, which only introduces complexity. With IPv6, each device will have the ability to have its own unique IP address. This facilitates direct communication between devices on the Internet, improving network efficiency and transparency.

Stateless Address Autoconfiguration

One of the major improvements made by IPv6 over IPv4 is stateless autoconfiguration. This feature simplifies the process of assigning IP addresses to devices, which no longer requires a central server. Devices can independently generate their own IP addresses using a combination of network prefix information and their unique MAC addresses. Since the MAC address of each device is distinct, this method ensures globally unique IP addresses without the need for manual configuration or DHCP servers.

More Efficient Routing and Network Management

IPv6 introduces a simplified addressing structure for more streamlined network management. Unlike IPv4, IPv6 headers are fixed-length. This streamlines packet processing, reduces overhead, and helps speed up routing and forwarding processes.

In addition, IPv6’s hierarchical addressing scheme allows for more efficient routing and aggregation of address prefixes. With IPv4, hierarchical addressing relies heavily on subnetting. That can lead to complex routing tables and inefficient use of address space. In contrast, the optimized IPv6 hierarchical addressing system results in more concise and predictable routing tables.

Increased Security

IPv6 incorporates built-in security features in the protocol. Those include IPsec (Internet Protocol Security), which provides end-to-end encryption, authentication, and integrity protection for data packets. The benefits of IPsec are enhanced privacy and increased network security.

By integrating security at the protocol level, IPv6 mitigates vulnerabilities present in IPv4 networks and ensures a higher level of protection against many security threats.

Enhanced Quality of Service

IPv6 comes with built-in features that improve QoS (Quality of Service) compared to IPv4. These include flow labeling and traffic prioritization, which make IPv6 more efficient at handling of network traffic. The QoS improvements provided by IPv6 help users achieve a better experience, especially when it comes to the IPv6 vs IPv4 comparison.

Why Is IPv6 Still Not So Popular?

IPv6 seems to be more modern and efficient than IPv4. So why did we say at the beginning of the article that IPv4 is still the most widely recognized and adopted version of IP? Here, there are two good reasons for that:

  • The benefits of IPv6 are not so evident to the average user: While tech enthusiasts may love IPv6, IPv4 is still good enough. As a rule of thumb, companies struggle to justify investment in a new technology when customers do not perceive a direct impact or significant value from it. The expansion of the IP address pool is critical for long-term scalability, sure. However, its effects may not be felt by until IPv4 addresses are exhausted. So, the urgency of IPv6 adoption is not felt by all stakeholders.
  • IPv6 and IPv4 are not directly interoperable: If a website operates on IPv6 but your device and ISP only support IPv4, you may experience connection issues. Although modern routers and devices generally support IPv6, the global transition requires updates for all devices and operating systems. Plus, maintaining compatibility with both protocols during the transition period comes with additional costs.

As you can observe, the IPv4 vs IPv6 debate is much more complex than expected.

Final IPv4 vs IPv6 Comparison

Some of the most notable differences between IPv4 and IPv6 are:

  • IPv4 is still the most adopted version of the IP protocol.
  • IPv6 has a 128-bit address space compared to the 32-bit address space of IPv4.
  • IPv6 addresses are much longer than IPv4 addresses, which means IPv6 addresses are harder to remember.
  • IPv6 includes built-in QoS.
  • IPv6 features IPsec.
  • IPv6 has longer, fixed-length packet headers.
  • IPv6 eliminates the need for NAT systems, obviating subnetting problems.
  • Multicasting is part of the basic specification of IPv6, while it is optional in IPv4.
  • IPv6 has more features than Ipv4, which leads to a more complex configuration.

For an immediate comparison, take a look at the IPv4 vs IPv6 comparison table below:

IP address4 numbers from 0 to 255, separated by periods (e.g., hexadecimal values separated by colons (e.g., 2001:db8:3333:4444:5555:6666:7777:8888)
IP address length32-bit128-bit
Number of IP addresses4.3 billion340 undecillion
Header lengthFrom 20 to 60 bytes40 bytes
Address typesUnicast, multicast, broadcastUnicast, multicast, anycast
Local address managementAddress Resolution Protocol (ARP)Neighbor Discovery Protocol (NDP)
Address configurationManual or via DHCPManual, SLAAC, DHCPv6
SecurityDepends on individual applicationsBased on IPsec
Encryption and authenticationNot providedProvided
FragmentationCarried out by the sender and forwarding routersCarried out only by the sender
Packet flow identificationNot availableAvailable
Checksum fieldAvailableNot available
VLSM supportAvailableAvailable


In this article, you learned what IPv4 and IPv6 are, what they have in common, and where they differ. In detail, you learned that IPv4 and IPv6 are two versions of Internet Protocol. IPv4 has been around for over 40 years and is still the most widely adopted, but Ipv6 promises to introduce many advantages and improvements.

Regardless of which IP protocol you use, your public IP provides information about who you are and where you live. There are several ways to hide your IP address, and the most effective way to achieve greater security and privacy is to use a proxy server.

Bright Data controls the best proxy servers in the world, serving Fortune 500 companies and more than 20,000 customers. Its offer includes a wide range of proxy types:

Bright Data offers proxy services for all IP types. Start your free trial now!


Which is more popular, IPv4 or IPv6?

As of this writing, IPv4 is still the most widely used version of the Internet Protocol. At the same time, the numbers are changing and IPv6 adoption is increasing.

Google maintains public statistics on IPv6 availability, so you can track IPv6 adoption on its official website.

How many addresses have IPv4 and IPv6?

IPv4 supports approximately 4.3 billion addresses, while IPv6 offers 340 trillion addresses.

Who wins the IPv4 vs IPv6 speed comparison?

Since IPv6 is not be adopted globally, there will be no clear winner in the comparison between IPv4 and IPv6 speeds. There is simply no clear answer, as there may not be enough data to back the benchmark. IPv6 should be faster than IPv4 due to the lack of NAT, faster routing and packet processing.

Should I use IPv4 or IPv6?

The choice to use IPv4 or IPv6 depends on various factors, such as network requirements, compatibility, and scalability needs. IPv4 remains widely used and supported in networks, but the Internet as a whole will gradually shift toward IPv6. Usually, browsers check whether IPv6 is supported by a website. If not, they send a request via IPv4. Thus, the use of IPv6 does not exclude IPv4.

Am I using IPv4 or IPv6?

To determine if you are using IPv4 or IPv6, you can check your network settings or use online tools like What Is My IP Address. Additionally, running the ipconfig command on Windows or ifconfig on Unix-like systems can reveal your IP address and indicate whether it is an IPv4 or IPv6 address.

Does it matter if your proxy provider does not support IPv6?

If your proxy provider does not support IPv6, it may limit your ability to access IPv6-only websites. However, accessing IPv4 content should not be a problem as most websites still support that protocol. If you need to deal with IPv6-enabled services or want future-proof connectivity, choose a proxy provider that supports all types of IPs, such as Bright Data.