The difference between IPv4 and IPv6

Today, the internet is like a massive highway, with users acting like thousands of cars driving up and down. 

Since each of those cars needs a license plate, every user connected to the internet needs an address. These addresses come in two versions: IPv4 and IPv6. 

The technology behind how our devices connect to the web is evolving. Now, we must keep our finger on the pulse. That’s why we’ll explain the difference between IPv4 and IPv6 and tell you why so many changes are happening. 

Who wins this round: IPv4 vs IPv6?

Let’s find out.  

Key takeaways: 

• IPv4 and IPv6 are two versions of the Internet Protocol (IP) 
• IPv6 emerged to overcome the limitations of IPv4, particularly the small address pool
• Transition methods for IPv6 include dual-stack, tunneling, and translation techniques
• Network professionals must leverage tools and resources for an easier transition

Quick overview of IPv4 and IPv6

Before we get to the technical bits, let’s meet our characters: what is IPv4 and IPv6? 

The first two letters (IP) denote that we’re talking about Internet Protocol. An IP is a set of numbers that identifies each device connected to a network. This is your device’s address that allows you to communicate with other devices with different addresses. 

Every device or domain in a network has a unique IP address. 

There are two versions of IP: IPv4 and IPv6. Contrary to their monikers, these IPs are the only two adopted and deployed versions in existence. 

IPv4 is the fourth version of Internet Protocol and the first version that went into use. The Advanced Research Projects Agency Network (ARPANET) launched it in 1983. IPv4 uses 32-bit addresses, a format most of us are familiar with, such as 192.168.1.1. 

Here’s what else we know about IPv4: 

• It’s still the most used format today
• It led to the creation of the Domain Name System (DNS)
• It does not provide any mandatory security measures 

IPv6 is the sixth, newer version of IP. It uses 128-bit addresses that contain both letters and numbers. The Internet Engineering Task Force (IETF) launched IPv6 in 1998 to overcome IPv4 limitations and prevent address exhaustion. The format of IPv6 addresses is more complex and looks like this: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

Other facts about IPv6 include: 

• It was standardized in 1998 but initiated in 1994
• It includes a built-in network security layer
• It’s compatible with newly developed devices

Since tech giants are already pushing for the transition to IPv6, we expect it to become a larger player in the Internet of Things (IoT) and the proliferation of new devices. In fact, over 99% of internal traffic at Meta is over IPv6. 

The larger address space can support billions of new devices, while the suite of security protocols can make IoT devices communicate securely. 

Before we get to the technical bits, we have to understand how IPv6 can ensure the company stays afloat amid a bevy of new, interconnected devices.

Key differences between IPv4 and IPv6

Although both IPv4 and IPv6 have the same goal – to assign unique addresses to devices connected to the internet – they go about differently. 

Since we don’t have days to wax poetic about protocols, we’ve compiled a table that compares how IPv4 and IPv6 stack up:

Why a transition from IPv4 to IPv6 is necessary

Now, since the difference between IPv4 and IPv6 is so large (and in favor of the latter), should you consider a transition? 

In the future, you’ll likely have to. Today, you may start thinking about it and taking proactive steps toward it. 

Due to IPv4 address exhaustion, new devices will inevitably adopt IPv6. In the 1980s, when the IPv4 first came into play, a pool of 4.3 billion IP addresses seemed plenty. But after just a few short years, it became apparent that we’d soon reach the last available value string. 

With the creation of IPv6, we can alleviate the exhaustion crisis and even delay it. 

For businesses, a transition to IPv6 can improve data protection and reduce the reliance on external security measures. The transition to IPv6 can lead to faster data transfer rates and reduce latency. What’s more, it can help curb costs, too. 

For end users, IPv6 can provide more reliable connectivity and make direct peer-to-peer communication possible without the complications of Network Address Translation (NAT). This means an improved mobile experience, more secure online transactions, and fewer compatibility issues with upcoming tech.

Although IPv6 adoption may seem far off, Google’s adoption statistics show that the percentage of people accessing sites over IPv6 has been growing since 2011. 

Source: Google IPv6

Worldwide, adoption rates are uneven. Despite IPv6 being present across all continents, some countries take the cake: 

• France (74.24%)
• Germany (74.07%)
• India (71.39%) 
• Malaysia (68.5%)
• Saudi Arabia (63.31%)

Source: Google IPv6

But enough of what the rest of the world is doing, why do you need IPv6 vs IPv4?  

• Scalability: IPv6 is the network of the future. The larger address ensures there are enough IP addresses for new devices, especially with IoT. IPv6’s improved support for routing also helps with large-scale deployments. 

• Security: IPv6 comes with end-to-end encryption, data integrity, and authentication. This means data protection is higher as it travels across networks. What’s more, with NAT no longer needed, communication between devices is more secure. 

• Efficiency: IPv6 allows for more hierarchical and aggregated IP address allocation. This reduces the size of routing tables and simplifies route lookups, leading to faster packet forwarding. With the simplification of the header, IPv6 also minimizes the processing burden on routers. 

What If You Don’t Transition?

Failing (or refusing) to transition to IPv6 can have economic implications for businesses, including: 

• IPv4 price inflation: The scarcity of IPv4 addresses has triggered a rise in costs for acquirement. Fighting for the remaining IPv4 addresses may lead businesses down a dark path. 

• Limited growth: The internet is in dire need of a more scalable networking infrastructure. Businesses that stand by will be unable to grow. 

• Lost competitiveness: As more organizations transition, those who don’t may fall behind. They may lose future opportunities and reduce interoperability with newer systems. 

• Limited compatibility: If future devices exclusively use IPv6, your business will be unable to communicate with them. 

Our DevOps expert, Kristian Razum thinks that “while a transition isn’t a pressing need right now, it’s better to take small steps toward that goal instead of waiting until the company’s cornered.” 

Other network professionals have shared similar opinions in anonymous forums, mainly suggesting dual-stack implementation as a way to bridge the gap. Some believe that complete migration is currently unnecessary, but they should be taking baby steps. 

In any case, network professionals should think about a transition plan to migrate. Taking proactive steps now will mean your organization remains competitive and capable of supporting the ever-growing number of devices. 

Don’t wait until you have to.

Transition mechanisms between IPv4 and IPv6

There are a few different ways to transition from IPv4 to IPv6. 

Familiarize yourself with the good and the bad of each mechanism to ensure you’re making the right choice. 

Dual-stack implementation

Dual-stack implementation means configuring your network to support the simultaneous use of both protocols. Most network professionals start with this approach because it facilitates interoperability between IPv4 and IPv6 during the gradual migration. 

This mechanism ensures a smoother transition because both devices can agree on which IP version to use. 

Dual-stack comes with its own pros and cons: 

• Provides backward compatibility: It allows devices to switch between IPv4 and IPv6 and ensures interaction with legacy systems. 

• Requires more resources: Operating both protocols requires additional resources, like memory and processing power, which may lead to higher operational costs. 

If you’re ready to implement dual-stack, follow these steps: 

1. Assess compatibility: Make sure your systems (routers, firewalls, servers, and clients) are compatible with IPv6. Most modern platforms natively support IPv6, but it won’t hurt to review the documentation or access the settings to confirm this.

2. Enable IPv6 on devices: Ensure that IPv6 is enabled on your networking hardware. Here’s an example of enabling IPv6 on a Cisco Router that configures the interface with both an IPv4 and IPv6 address: 

enable
configure terminal
ipv6 unicast-routing
interface GigabitEthernet0/0
ip address 192.168.1.1 255.255.255.0
ipv6 address 2001:db8::1/64
exit 

Ensure the DNS supports A records and AAAA records. It should look like this: 

example.com.       IN       A          192.168.1.10
example.com.       IN       AAAA       2001:db8::10    

3. Test connectivity: Use a ping to test your connectivity over both protocols: 

IPv4: ping 192.168.1.10

IPv6: ping6 2001:db8::10

You should receive a response from both addresses to confirm that the system can communicate using both protocols. If you use UptimeRobot’s ping monitoring service, you’ll always know where and when there’s room for improvement.  

Starting with critical systems first, including servers, databases, and core network infrastructure. That way, you’ll test the most important parts of your network and ensure they’re stable for deployment. 

Move on to less essential components only when you’re sure everything functions correctly. 

Tunneling methods

Alternatively, use tunneling methods that allow IPv6 traffic to be transmitted over existing IPv4 infrastructure. 

Since many networks are still IPv4, tunneling will help with the gradual adoption of the new protocol without an immediate overhaul of network infrastructure. 

There are several common tunneling methods, along with example configurations on a Cisco router: 

• 6in4 tunneling: This is one of the simplest methods. It encapsulates IPv6 packets inside IPv4 headers. It’s useful when parts of a network support IPv6 but must traverse regions that are still IPv4-only. It requires manual configuration of the endpoints, so both the source and destination must have static IPv4 addresses. 

enable
configure terminal

ipv6 unicast-routing

interface Tunnel0
ipv6 address 2001:db8:1:1::1/64         # Your assigned IPv6 address
tunnel source 192.0.2.1                  # Your local IPv4 address
tunnel destination 203.0.113.1            # Remote IPv4 address
tunnel mode ipv6ip
no shutdown

ipv6 route ::/0 Tunnel0

exit
exit

• 6to4 tunneling: This is an automatic tunneling method that facilitates the transmission of IPv6 packets over IPv4 networks without a manual tunnel configuration. The IPv4 network encapsulates IPv6 traffic and automatically generates an IPv6 address from the original IPv4 one. 

# Enable IPv6 unicast routing
Router(config)# ipv6 unicast-routing

# Configure the 6to4 tunnel interface
Router(config)# interface Tunnel0
Router(config-if)# ipv6 address 2002:C0A8:0101::1/64  # IPv6 address derived from public IPv4
Router(config-if)# tunnel source <ipv4-public-address>
Router(config-if)# tunnel mode ipv6ip 6to4
Router(config-if)# exit

# Add IPv6 route to the tunnel
Router(config)# ipv6 route ::/0 Tunnel0

• Teredo tunneling: This method is best for devices behind NAT. It encapsulates IPv6 packets within IPv4 UDP packets and allows IPv6 connectivity even when the network is using a private IPv4 address. Teredo is still around, but its usage has declined dramatically. 

enable
configure terminal

# Enable IPv6 routing
ipv6 unicast-routing

# Create a Teredo tunnel interface
interface Tunnel0
ipv6 address 2001:db8:1:1::1/64            # Your assigned IPv6 address
tunnel source <your-public-ipv4>           # Your public IPv4 address
tunnel mode teredo

# Bring up the tunnel interface
no shutdown

# Add a default route for IPv6 traffic
ipv6 route ::/0 Tunnel0

exit
exit

Note: Cisco devices may not support the automatic setup of a Teredo server. Check 

            If you have a reachable server beforehand. 

• 6th: Rapid Deployment of IPv6 is an automatic tunneling mechanism that enables ISPs to rapidly deploy IPv6 across their existing IPv4 networks without significantly changing the infrastructure. This method is an evolution of 6to4 and addresses some limitations.  

# Enable IPv6 unicast routing
Router(config)# ipv6 unicast-routing

# Configure the 6rd parameters
Router(config)# interface Tunnel0
Router(config-if)# ipv6 address 6rd-prefix 2001:db8::/32  # 6rd prefix provided by the ISP
Router(config-if)# tunnel source <ipv4-interface>  # Interface with public IPv4
Router(config-if)# tunnel mode ipv6ip 6rd  # 6rd mode
Router(config-if)# 6rd ipv4-prefix 0.0.0.0/0  # Use any IPv4 address

# Add route to send IPv6 traffic through the 6rd tunnel
Router(config)# ipv6 route ::/0 Tunnel0

Keep in mind that IPv6 tunneling adds overhead. Since it adds extra headers to encapsulate the original packet, it increases the overall packet size. 

This extra information consumes additional bandwidth and may thwart network efficiency, including CPU and memory usage. Sometimes, it may also cause fragmentation if the resulting packet exceeds the maximum transmission unit (MTU). 

If overhead is an issue, stick to manual tunnels. 

Translation techniques

Translation techniques facilitate a transition from IPv4 to IPv6 while maintaining connectivity with legacy systems. Using protocol translation will allow IPv6-only hosts to communicate with IPv4-only hosts.

Implementing translation techniques makes way for a gradual shift to IPv6 without worrying whether the existing IPv4 services remain accessible. 

NAT techniques for translation, like NAT64 or NAT46, use DNS64 to translate between the two protocols within the provider’s network. This means there’s little burden on connectivity. 

Here’s how that works: 

Source: A10 Networks

NAT64/DNS64 is what you’ll likely be working with if you need translation. NAT64 operates by translating IPv6 packets into IPv4 packets (hence ‘64’ in the name). This allows IPv6 clients to access IPv4 services by embedding the IPv4 address within a specific IPv6 address format. 

Meanwhile, DNS64 synthesizes AAAA records for domain names that only have A records. This is how you get interoperability, transition gradually, and stay connected to IPv4 resources.

Tip: Have a plan in place. The transition from IPv4 to IPv6 can create issues that disrupt network operations. Assess the infrastructure and services and take note of the compatibility. This is the best way to avoid misconfigured address translations or incomplete DNS records. 

Practical steps for transitioning to IPv6

Ready to take the leap?

Before you do, we recommend downloading our handy checklist to guide you during the transition and keep your team on track.

Let’s talk about the most crucial steps in your plan: 

Network assessment and planning

Like with any major change, you can’t dive in with both feet. 

You need a bird’s-eye view of your network to understand how your tweaks may affect each component. This is what you need: 

1. Inventory assets: List all hardware and software components connected to your network. Check on your inventory during the transition to ensure you’ve assessed the change with each component. 

2. Evaluate compatibility: Use the tools at your disposal (and listed below) to determine how compatible your network is with IPv6. Check for hardware and software readiness to see whether connected devices support IPv6 natively.  

3. Identify upgrade needs: Check the documentation for firmware updates or software patches that can bridge any gaps for devices that don’t support IPv6. If no update is available, see how you can replace the component. Always prioritize critical infrastructure that manages traffic directly. 

4. Develop a transition timeline: Set milestones depending on the size and complexity of your network. Small networks may transition in months, but larger ones may take years. If your boss wants a change in a month (yes, this happens), be prepared to give them reasons why it’s impossible and have a feasible agenda ready. 

Implementing IPv6 on network devices

After completing the preparatory stage, move on to implementation by following these steps: 

1. Update firmware/software: For devices that need updates, download the appropriate one and review the release notes to grasp the features. Back up the device’s configuration to prevent data loss. Then, verify the update and test functionality. 

2. Configure IPv6 settings: Assign IPv6 addresses to each connected device. You can use a combination of static addressing for core infrastructure and automatic configuration (SLAAC or DHCPv6) for end devices. 

3. Adjust security policies: Review and update firewall rules, intrusion detection and prevention systems (IDS/IPS), and access control lists (ACLs) to accommodate IPv6 traffic. Check how IPv6 handles fragmentation, spoofing, and multicast. 

4. Test network functionality: Use testing tools to verify IPv6 connectivity. Check routing tables, see if IPv6 traffic is properly forwarded, and validate the dual-stack configuration. Always pilot-test on a smaller network segment and monitor critical services with UptimeRobot to ensure they stay online. 

Updating applications and services 

Since many applications were designed with IPv4 in mind, they’re not optimized to function properly with IPv6. As a result, the last step in your transition should be updating applications and services to support IPv6 addresses. 

Here’s what you should check: 

• Load balancers
• Email servers
• Web servers
• Firewalls
• DNS
• VPN

Compile a list of your critical applications and evaluate vendor support for IPv6. This may be a long and tedious process, depending on how comprehensive the vendor documentation is or how responsive their representatives are. Regardless, if you want a secure network that properly handles traffic, don’t skip this step. 

Security implications of IPv6

IPv6 is all well and good thus far, but how does it affect security? 

While we briefly touched on this point above, we’ll go into more detail now.  IPv6 impacts security in a plethora of ways, including: 

Enhanced security features

IPv6 features improve upon IPv4 security in many ways. 

Besides IPsec, IPv6 includes other security benefits like: 

• Larger address space makes it harder for attackers to perform network reconnaissance or launch scanning attacks 

• IPv6’s simplified packet headers improve the performance of security tools and reduce overhead on appliances 

• The Neighbor Discovery Protocol (NDP) in IPv6 includes security extensions that prevent additional threats 

• The elimination of NAT allows direct peer-to-peer communication and improves policy transparency, which also simplifies VPN setups and performance. 

Security is one of the key features of IPv6 and one of the many reasons why over 42% of Google’s traffic is over this protocol. In the future, we expect more developments to spring up and solidify the security IPv6 boasts. 

New security challenges 

But not everything is sunshine and rainbows. 

Despite the security benefits, IPv6 unearths new challenges that might plague organizations in the future. 

The largest potential problem is simultaneously the most prominent benefit of IPv6: the larger address space. 

With so many new addresses popping up, traditional scanning techniques may be rendered ineffective. 

In IPv4, attackers often rely on port scanning to identify vulnerable hosts within a network. Now, the sheer volume of potential IPv6 addresses makes such scanning impractical, time-consuming, and unfeasible. This sounds great, but it’s likely a false sense of security. 

Namely, organizations may start to believe they’re untouchable because scanning is more difficult. Thus, they’ll invest fewer resources in protection. This opens the door for issues like: 

• The potential for new types of attacks 
• The need for updated security strategies 
• The possibility of misconfigurations 
• Security tools that do not support IPv6 
• A lack of awareness and training among IT professionals 

Maintaining IPv6 should be an ongoing endeavor and not a set-it-and-forget-it deployment. Businesses should invest in the continual education and training of their network staff to ensure no networks are exposed to threats. 

Best practices for IPv6 security

So what can you do to affirm security with IPv6?

Our research brought up a few useful practices to follow: 

• Update firewalls: Deploy IPv6-aware firewalls and filter traffic based on the company’s security policies.

• Use Secure Neighbor Discovery (SEND): Implement SEND to protect against NDP-related attacks like spoofing.

• Monitor network traffic: Use tools to scan for unusual traffic or anomalies that may indicate an incident. UptimeRobot is one tool that can keep you up-to-date with a comprehensive 30-second website check and alert.

• Filter IPv6 traffic: Block all IPv6 traffic if you haven’t yet deployed it, even if it’s tunneled in IPv4. 

• Plan for problems: Address any issues before implementation to avoid security pitfalls.

If you want more detailed insights, check out these sources: 

• Cisco IPv6 Security Best Practices 
• CISA’s Guidance on IPv6 Security 

Common misconceptions about IPv6

Despite the suite of information on IPv6, forums and threads are rife with misconceptions. This doesn’t surprise us considering the complexity and technological ingenuity the IPv6 comes with. 

So, let’s set the record straight and bust the most common myths floating around: 

Tools and resources for IPv6 transition

Now that you know the differences between IPv4 and IPv6, start thinking about the right time to transition. 

Since it’s no longer a matter of if but when, let’s talk about the tools and resources available to walk you through the transition: 

• IPv6 readiness assessment tools: These tools help organizations evaluate their current network infrastructure, systems, and applications. Essentially, they determine how prepared you are to support IPv6. With this, you can identify potential issues, get guidance, manage risks, and transition smoothly. 

• Configuration guides: These guides ensure the hardware operates efficiently within the system. Use the guides from your hardware vendors as documentation to configure and optimize servers and devices. Plus, you’ll learn the necessary steps to diagnose and resolve issues during and after installation. 

• Training programs: IPv6 training programs cover various aspects of the protocol, from fundamentals to deployment. This knowledge equips professionals to future-proof networks and address security challenges before they become critical. This is how businesses keep up the pace and IT staff remain competitive. 

It’s human nature to resist change and stick to what’s worked thus far. Still, technological advancements wait for no one, so if you’re not up to speed, you’re falling behind. 

Here are some resources and tools to help you separate fact from fiction: 

Future predictions 

It’s hard to tell what the future holds for anything internet-related. Tides are shifting in the blink of an eye, so anything we’d expect today may be rendered obsolete tomorrow. 

Still, we can speculate. 

The surge of internet growth and the influx of demand for new IP addresses bodes well for IPv6. Yet, Razum, our DevOps expert, doesn’t think IPv6 will completely replace IPv4 anytime soon. 

He had this to say: “Right now most users are fine coasting with IPv4, it doesn’t pose a risk. But if we completely ignore the benefits of IPv6, we’ll miss out on many developments and risk facing issues in the future.”

Since large enterprises are spearheading the transition, it’s safe to say that in a few years, we’ll prioritize this more robust internet infrastructure and view it as a foundational element of company and industry progress.

While you’re at it, don’t forget to keep an eye on your infrastructure and important IPs. Let us ping them for you and send you notifications once your attention is needed, you can start monitoring in just a few clicks!

Written by

Mila Kalajdjieva

Mila is a content marketer, writer, and dog mom working in marketing for over 3 years. She holds a Bachelor’s in English, a Master’s in Digital Marketing, and has experience teaching and tutoring. When blessed with free time, she wanders Europe trying foods she can’t pronounce, but she’s mostly busy taking photos of her dog sleeping.