Rackspace is Gearing Up for IPv6

Jason Ackley, a Network Architect for Rackspace Backbone Engineering, is leading the global IPv6 deployment and IPv6 evangelization for Rackspace.

We’ve been fielding a lot of customer questions on the topic of the dwindling amount of remaining IPv4 address space available and the world-wide deployment of Internet Protocol version 6 (IPv6), so we’ve decided to address the topic here. As a Network Architect, who’s been working on the global deployment of IPv6 at Rackspace, I could talk for days about IPv6, but I’ve intentionally kept this blog at a high-level to give you an overview of the current situation.

Why is IPv6 Important?

If you search for “IP exhaustion” online, you’ll find many IPv4 “countdown clocks.” The IPv4 unallocated pools are at about 2% as of this writing. This number represents the highest level blocks that are assigned to downstream Regional Internet Registries (RIR). These blocks are then assigned to hosting providers, such as Rackspace and access providers, such as Comcast.

The underlying number for an IPv4 address is an unsigned 32bit integer, which provides for roughly 4.2 billion values. The exact number can be seen here. For various reasons, the entire space is not available for use. We’d have to enter uber-geek territory to explain why that is. Due to the nature of the protocols, we simply can’t add more digits to the end of the number and call it a day.

The current widely deployed Internet Protocol is version 4, or simply IPv4 for short. While DNS provides us the mapping service from a common name, such as www.rackspace.com to an IP address, the underlying IP addressing structure is indeed finite, and we as an industry are approaching the limits of the numbering system. Enter IPv6.

IPv6 to the Rescue

Due to the rapid growth of the internet during the boom years, the Internet Engineering Task Force began to create a newer protocol to address the shortcomings of the IPv4 protocol.

These efforts were published in late 1998 and IPv6 was born. Since IPv6 is a completely different protocol, it’s not compatible with existing IPv4 systems. Luckily, we have special transition mechanisms (e.g. NAT64) that we can use with varying levels of success. Look for more details about that in future posts.

One of the biggest differences and main benefits is that the IPv6 address size is increased to a 128bit integer, providing a virtually unlimited supply of IP address space for everyone. IPv4 only provides a mere 4.2 billion IP addresses. However, IPv6 provides a nearly infinite amount at 340 undecillion. Enough to assign eight billion IP addresses to each atom in the body, of the entire population of the world.

How is Rackspace Addressing IPv6?

Because this is an industry-wide issue, not just a Rackspace-specific problem, we’ve been working with suppliers, industry peers, and internally for quite some time on IPv6 solutions; so that we can prepare and help enable our customers for IPv6 as seamlessly as possible.

As you can imagine, anything that uses, updates, or manipulates an IP address has to be checked and updated for IPv6 compatibility. This includes internal software tools, firewalls, routers, and other network-centric devices.

Rackspace has also been performing datacenter upgrades that will continue through the first half of 2011. These upgrades will occur during normal Rackspace engineering maintenance windows, as well as, supplemental maintenance windows introduced to accommodate our rapid deployment plans for IPv6.

Although we’re doing our part as a hosting provider to ensure our customers are prepared for IPv6 utilization, there are still some operational functions on the side of our customers that must be considered. If you’re a business owner, now is the time to start constructing your list of vendor dependencies, reviewing your website software applications, and checking to see if you have any hard-coded IPv4 addresses in your configuration to ensure that you avoid incompatibility issues. If you need assistance with this, our support team is always here to help.

Have IPv6-related Questions?

Introducing such sweeping changes takes time to propagate to everyone within a large company. In order to provide the best customer results, please submit your IPv6-specific questions to ipv6@lists.rackspace.com. If you’re not currently a Rackspace customer, I encourage you to contact your hosting provider and the internet provider for your office to inquire about their IPv6 readiness plans.

As always, stay tuned into the Rackspace Official Blog for updates on IPv6 and other exciting Rackspace news and developments!

Rack Blogger is our catchall blog byline, subbed in when a Racker author moves on, or used when we publish a guest post. You can email Rack Blogger at blog@rackspace.com.


  1. As a rackspace customer, it is interesting to find out that you are quite slow to step up to the place on this issue. I had kind of hoped that you would have been addressing this for at least the last year.
    Now, my real questions are,
    1) Will you do a dual stack like Google hosting and Comcast do (though comcast is in the middle of their testing)?
    2) How soon before you are ready and how soon can we start adding IPv6 to our systems?

  2. Thanks for bringing this issue to the table, finally. It is so important for everyone in the near future including us RSC customers, that I’m worried by the lack of reply to this thread and the previous commenters question especially. Is there a roadmap available?


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