IPv6: Managing The Transition

The Internet is a gargantuan system, reaching over the last 50 years a scale so massive that it can barely be mapped. At the center of this colossus, however, is a group of humble but mighty protocols, known collectively as the Internet protocol suite or TCP/IP, which form the bedrock of the Internet as we know it. Arguably the most important of these in establishing the modern internet is the aptly named Internet Protocol, or IP.

Over the last few decades, however, the Internet Protocol has been in the midst of an important transition, from the older version 4 (IPv4) of the protocol to the newer version 6 (IPv6). In this article, we will cover the origins of the transition, the differences between the two versions, and a sometimes-overlooked aspect of the transition: the potential security implications of the switch, and how organizations can manage the transition to avoid any pitfalls.

IPv4 - The “Old Reliable”

IPv4, the once-ubiquitous version of the Internet Protocol in use since the early 1980s, has its origins in the Transmission Control Program, developed by Defense Advanced Research Projects Agency (DARPA) Engineers Bob Kahn and Vinton Cerf in 1974. The original Transmission Control Program lacked an Internet Protocol as an independent specification, which emerged by 1981 after a series of changes to the Transmission Control Program, as IPv4.

The following year, in 1982, the US DoD adopted TCP/IP for military computer networking, and with the US military’s migration to TCP/IP in 1983, the Internet protocol suite began its reign as the dominant system of protocols used for computer network communication.

The development of TCP/IP represented a major innovation in computer networking, popularizing end-to-end communication where reliability and security are handled by the end nodes in the network, rather than the network itself, with the Internet Protocol simply dictating how traffic is routed and transmitted.

A key component of IPv4 is the IP address system. Just like homes and businesses each have a unique address associated with them, communication through the Internet Protocol is facilitated by the existence of an IP address associated with each device connected through the Internet (this is a simplified explanation; you can read a more detailed run-through of IPv4 here).

The IPv4 standard worked well for decades, laying the foundation for the internet’s explosive growth. However, since its inception, IPv4 has had a major limitation, which has resulted in the need for a new version of the standard.

IPv4’s “Exhaustion Problem”

Like many important inventions, the Internet Protocol didn’t start off as something intended to facilitate communication between billions of devices around the world. Rather, as Vinton Cerf himself has stated, the internet began as an experiment. As such, IPv4 used a 32-bit address scheme, which allowed for a maximum of roughly 4.3 billion unique addresses, with many being reserved for specific purposes and organizations.

At the time of conception, this many addresses were considered to be more than sufficient. With more and more people, and by extension an ever-increasing number of devices making use of the internet, the 4.3 billion number has become an increasingly obvious limitation.

To combat the exhaustion problem, a number of stop-gap solutions have been implemented over the years, including Network Address Translation (NAT) which allows for multiple devices on a private network to share a single public IPv4 address, Classless Inter-Domain Routing (CIDR) to reduce excess address allocation, unnumbered interfaces to reduce address usage by transit links, and IP address recycling.

However, the fundamental problem remained; that there would one day be too few addresses for too many devices.

IPv6 - The New Kid on The Block

The eventual problem of IP exhaustion was clear as early as the 1980s, and even as stop-gap solutions were being implemented, work was underway on a long-term fix. The result of those efforts was IPv6—a major revision to the protocol intended to solve the exhaustion problem once and for all.

While there are other improvements as well, the main change in IPv6 is the use of a 128-bit system instead of 32 bits, expanding the number of possible IP addresses from 4.3 billion to 340 undecillion, more than what will probably be needed for a long, long time—perhaps forever.

The switch from IPv4 to IPv6 has not been immediate, however. IPv6 adoption stands at 42-48% globally (the exact number fluctuates daily), with rates varying wildly between countries. In addition, many large organizations are either still in the process of transitioning or have not yet begun the transition to IPv6.

Security Implications of the Internet Protocol Transition

On its own, IPv6 isn’t necessarily more or less secure than IPv4 is; the underlying standards are quite similar. The security implications of IPv6 come into play primarily through the human factor as organizations enter the early stage of their transition to IPv6. These potential risks include:

1. Lack of training and education: Arguably the biggest risk factor in the IPv6 transition is a lack of adequate knowledge around the differences that do exist with IPv6, and how to deal with them accordingly from a network security perspective. While organizations are very familiar with IPv4, changes with IPv6 such as auto-configuration, lack of NAT, and multiple address hosts, amongst others, may not be fully understood even by professionals, opening the door to misconfigurations resulting in vulnerabilities.

   
   

   This may be exacerbated when organizations have to deal with a dual-stack structure with IPv4 and IPv6 protocols being run on devices simultaneously, requiring even more careful management and a greater possibility of misconfiguration.

2. Inadequate tools: Somewhat related to the previous point, another risk factor with IPv6 is organizations continuing to use inadequate security tools and techniques, either because of lack of knowledge and training, inertia from switching from practices that were tried-and-true with IPv4, or a lack of alternatives available on the market (though this last one is much less of a problem every year with IPv6’s continuing maturation).

   
   

   For instance, rate limiting, a common security tactic with IPv4 to defend against DoS attacks, is much less feasible with IPv6 given how difficult it is to apply to a vast 128-bit address system. Similarly, logging and SIEM systems may need to be reconfigured to work with IPv6, and a failure to do so, whatever the reason, may leave organizations vulnerable.

Managing the IPv6 Transition

Given the potential risks that come with transitioning networks to support IPv6, there are a few important steps organizations can take to avoid the pitfalls.

1. Adequate Training (Not Just for Critical Roles!)

The biggest step organizations can take towards a successful transition is making sure employees have sufficient knowledge of the differences that come with IPv6 and how that affects their work. Ideally, this extends not just to employees in critical roles in the transition, but also those more peripherally involved. Having a well-trained and informed staff is the most important defense against the sort of errors that could spell trouble from a network security perspective.

2. A Well-Defined Plan

Having a well-defined and thought-out transition plan is crucial to successfully moving a network to IPv6, especially for larger organizations with more complex networks. A good plan includes covering all the bases, from top to bottom, detailing how devices, network architecture, and even staff responsibilities will be handled in the transition process.

3. Making Use of Available Resources

Finally, there are a number of excellent resources available to assist organizations in making a seamless transition. In particular, the NSA’s “IPv6 Security Guidance” and RFC 7123: “Security Implications of IPv6 on IPv4 Networks” are fantastic jumping-off points for security considerations that should be taken into account with regards to IPv6 and should be given a read at or prior to the beginning of the transition process.

Conclusion

For businesses and organizations, managing the IPv6 transition may seem like a daunting task at first. But by taking a strategic approach, organizations can make the move to IPv6 in a way that supports their long-term growth while minimizing operational risks. The sooner organizations start the transition, the sooner they will be able to iron out any kinks they may face and emerge better off for it in the end.