IPv4 vs IPv6: Which Should You Use?

IPv4 and IPv6 are the two versions of Internet Protocol (IP). They influence how we exchange data through the web, impacting everything from gaming and browsing to VPN usage and online security. In short, they set the stage for how internet traffic moves.

While both protocols have been around for decades, many people still get confused about what an IP is and why we have two of them. But with IPv6 on the rise, it’s important to understand how these two protocols impact the way we use the internet. If you’re ready to learn about how they differ, keep reading! We’ll give you a rundown of everything you need and want to know about IPv4 vs. IPv6.

First Things First: What Is IP Addressing?

Picture a post office that receives parcels and letters, sorts them, and ensures correct and safe delivery to their intended destinations. This is how Internet Protocol (IP) addressing works.

IP is a set of rules or guides that ensures accurate data transfer across networks. Data travels over the internet in packets, which are smaller segments of whole files or data blocks. Each packet is tagged with IP information, which helps routers determine the correct destination for the traveling data. In this scenario, the packets are the parcels, while the IP addresses are the contact information for the sender and receiver.

Every device or website connected to the internet is given a unique IP address, and there are two kinds: IPv4 and IPv6.

IPv4 and IPv6 stand for Internet Protocol version 4 and version 6, respectively. IPv4 was first implemented in 1983, making it the most widely used protocol today. IPv6, on the other hand, was introduced in the late 1990s to resolve the limitations of IPv4. This newest version tackles security and privacy issues. Plus, since its IP addresses are longer, iPv6 accommodates a larger number of unique IP addresses.

How Does IPv6 Differ From IPv4?

In a nutshell, the differences between IPv4 vs. IPv6 can be summed up accordingly:

While the difference between the two may not seem important to day-to-day users, IPv6 boasts upgrades with long-term benefits. We highlighted below the most notable advantages of IPv6 over IPv4:

1. Longer Addresses

IPv4 addresses are what you often see online, appearing like 192.168.1.1. Its digit count may vary, with the numbers ranging from 0 to 255. So, a device’s IPv4 address can be anything between 0.0.0.0 and 255.255.255.255. This is called a 32-bit format using a decimal number (1–10) system.

The unique combinations in IPv4 can support around 4.3 billion IP addresses. While this figure may sound huge, it’s actually not enough for the vast number of devices that people around the world use to access the web.

To address the problem of insufficient IPv4 addresses, IPv6 was crafted with a more complex string of numbers and letters (hexadecimal system) separated by colons. An IPv6 address would look like 3002:0bd6:0000:0000:0000:ee00:0033:6778. This is the 128-bit format, and it supports 2¹²⁸ unique addresses — that’s 340 trillion trillion trillion IP addresses!

2. Streamlined Packets

Headers are packet labels containing the information needed to transmit data from one computer to another. In the example of parcel delivery, the packet header is the manifest that details the sender and receiver information as well as the contents of the package.

Header Size

Although IPv4 headers can range from 20 to 60 bytes, they’re often limited to only 20. This takes up comparatively less overhead than IPv6’s 40-byte headers. However, IPv6 headers are much simpler, translating to faster data transfer.

Checksums

Although IPv4 headers can range from 20 to 60 bytes, they’re often limited to only 20. On the other hand, IPv6 headers have 40 bytes but can usually transfer data faster. This is because IPv6 headers are much simpler. For instance, they have removed certain unnecessary elements, such as checksums.

IPv4 relies on checksums to detect errors in transit. However, checksums only spot discrepancies in the packet header, allowing corrupted data within the packet payload to go undiscovered. Plus, they can be intentionally altered by cyberattackers. In other words, they consume more data processing and transfer time and provide little in the way of security.

Packet Fields

IPv6 headers also replaced IPv4’s Options field with the Next Header field. The old section was used for optional tasks, such as testing, security, and specifying packet paths. Meanwhile, the new 8-bit section displays the header of the next packet, allowing seamless integration of future technologies and extensions.

Fragmentation

In IPv4 addressing, the sender and all forwarding routers can fragment packets to facilitate data transfer. This is an obvious downside because it exposes the packets to loss, where the protocol will then need to retransmit the entire packet to recover lost fragments. The overhead will also increase with the number of headers that need processing.

IPv6 doesn’t allow fragmentation in transit. Here, only the source node is allowed to fragment packets, enhancing data integrity and protocol performance even with low bandwidth.

QoS Handling

Quality of Service (QoS) refers to using protocols and technologies to optimize network traffic and prioritize performance-intensive applications. By allowing packet flow identification, IPv6 addressing enhances QoS handling.

IPv6 headers include a Flow Label field that displays a packet’s location in the data block. This ensures that packets are positioned correctly and prioritized in transit, which is especially crucial for dynamic media data like video and audio. IPv4 lacks this functionality.

3. Easier Configuration

IPv4 addressing accommodates both DHCP and manual configuration. DHCP stands for Dynamic Host Configuration Protocol, and it designates IP addresses to devices. The most common example of a DHCP server is the router in a home network. This protocol protects against potential errors that could happen during manual configuration, which is when human network administrators assign the IP addresses.

With IPv6, the configuration can be made through either SLAAC (Stateless Address Auto-Configuration) or DHCPv6. While DHCPv6 simply uses an updated version of DHCP to generate IP addresses for an IPv6 host, SLAAC automatically assigns and tracks IP addresses internally. So, IPv6 makes configuration easier and more intuitive since there are no servers or databases collecting or managing device information.

4. Reliable Transmissions

Both IPv4 and IPv6 offer multicast and unicast transmission types. However, IPv4’s default is broadcast, wherein one host or computer sends data to all other computers in the network.

On the other hand, multicast is the base setting in IPv6 addressing. In this protocol, a host can transmit a message to selected computers in the network. This prevents transmission bottlenecks and enhances data security by preventing unintentional data transfer.

5. Upgraded Security

Aside from tackling the inadequacy of IPv4 addresses, IPv6 was created with the most advanced security settings. IPv4 has no mandatory security measures, encryption, or authentication settings, and IPv6 solves that.

For instance, IPv4 comes with Internet Control Message Protocol (ICMP), which was designed for error reporting and diagnostics. However, ICMP has been known to be vulnerable to threats, resulting in malware transmission. IPv6 was executed with built-in IP security (IPsec) to address this issue. It’s a protocol that enhances network communications by setting up secure connections through encryption and authentication.

6. Better Speeds

IPv6’s advanced features make it naturally faster than its predecessor. First, its simplified packet headers make data transfer seamless. Its strict fragmentation rules also reduce transmission errors.

Also, IPv6 renders Network Address Translation (NAT) — which was implemented in response to the shortage of IPv4 addresses — useless. Since IPv6 provides near-unlimited unique addresses, it no longer needs NAT. In short, it promotes end-to-end connectivity between devices and websites, which often results in a faster connection.

Is IPv6 VPN-Friendly?

Despite all its benefits, most VPNs still lack support for IPv6. So, if your device is running IPv6, and you connect to a VPN that only operates on IPv4, the VPN will compromise by sending your traffic through an external IPv6 DNS server outside the VPN’s route. This could leak your IPv6 address, which makes the VPN useless.

For example, if you’re on IPv6 and using an IPv4 VPN to access geo-restricted Netflix content, an IPv6 leak means that Netflix may potentially detect your real IP address and location, allowing it to block you from the platform. Plus, an IPv6 leak may expose your online activities to your ISP.

To prevent this, you may either disable IPv6 when using a VPN or find a VPN with IPv6 leak protection. Here’s how you can check if your VPN backs IPv6:

1. Connect to your VPN on your device.
2. Head to IPv6-test.com.
3. Wait for the site to run its tests.

The test will also display your public IP address, ISP, and other IP-related information.

Editors' Note: Expressvpn and this site are in the same ownership group.

IPv4 vs. IPv6: Which Is Better for Gaming?

Given its technology upgrades, there’s no doubt that IPv6 can improve your gaming experience. First, it bypasses NAT, automatically reducing latency and offering smoother gameplay. Its multicast setting also streamlines how data is sent from one computer to another. Since it can target specific groups of computers — in this case, players — data is more accurately transferred, eliminating clogging and optimizing bandwidth usage.

In addition, IPv6’s built-in QoS allows data packet sequencing. In other words, it can prioritize gaming-related traffic, boosting gameplay speeds.

That said, you have to consider whether the game you’re playing supports IPv6. Otherwise, you don’t have a choice but to stick with IPv4. Also, in multiplayer games, it’s best to have both IPv4 and IPv6 activated so you can reach players who only have IPv4 connections.

How Do You Enable or Disable IPv6?

Learning to manually activate or deactivate IPv6 on your devices will allow you to optimize internet and app usage. Check out the instructions below:

On Routers

1. Enter your router’s default IP address or login URL on a web browser.
2. Click Advanced and select IPv6.
3. Enable or disable IPv6.
4. Select Save.

On macOS

1. Open System Preferences and select Network.
2. Click Advanced > TCIP/IP.
3. Click the Configure IPv6 dropdown, select Link-local only, and click OK.
4. Restart your device to apply the changes.

On Windows 10

1. Open Settings and go to Network & Internet.
2. Click Status > Change adapter options.
3. Right-click on your activated network and choose Properties.
4. Check or uncheck Internet Protocol Version 6 (TCP/IPv6) to enable or disable IPv6.
5. Click OK to save and restart your device.

On Linux

1. Open Terminal and log in with root access.
2. Add the following lines to the /etc/sysctl.conf file:
   • net.ipv6.conf.all.disable_ipv6 = 1
   • net.ipv6.conf.default.disable_ipv6 = 1
   • net.ipv6.conf.lo.disable_ipv6 = 1
3. Save the file and reboot using $ sudo reboot.

Should Devices Have Both IPv4 and IPv6?

Since many software, applications, and companies still operate on IPv4 alone, it’s best to keep both IP versions activated. IPv4 ensures that all websites and networks remain accessible, while IPv6 improves security and performance.

Additionally, avoid manually disabling IPv6 if it’s activated by default. Sometimes, your ISP may already be mainly using IPv6, so deactivating it can cause connectivity issues.

Why Isn’t Everyone Switching to IPv6?

The latest Google trends show that global IPv6 adoption is still below 50%, even though it’s been nearly three decades since it was first introduced and implemented. RIPE Network Coordination Centre — the internet registry covering Europe, Central Asia, and the Middle East — estimates that the transition won’t be complete until 2030 or beyond.

Companies are currently the most adamant about sticking to IPv4 operations, as transitioning to IPv6 takes time, money, and effort that they’d rather not spend. Plus, no enterprise wants to be the first to switch. They know that the trailblazer would most likely suffer losses from trials and errors, and they might want to avoid this by letting other businesses go first. But, since IPv4 is still perfectly functional, no one seems to be stepping up to the plate.

As for individual users and applications, compatibility is the main roadblock to moving to IPv6. Backward compatibility was not taken into account when creating IPv6, which means users can’t access IPv4 websites and software unless they have both versions activated on their device.

Still, the full IPv6 transition is inevitable. It will likely happen through incremental changes to spare end users from dealing with incompatibility and network failures. Once the transition is complete, we can all expect to benefit from the upgrades and advances of this newer IP version.

Wrapping Up

Ultimately, IPv6 offers users everything that IPv4 can’t: an abundance of addresses, hardened online security, faster data transfer, and more. Even so, IPv4 remains relevant and relied upon by most of the world.

So, to get the best of both worlds, we recommend activating both protocols on all your devices. That way, you would be well-equipped to adapt to online technology advancements that are sure to come.