IPv6: Your Questions Answered!

David Barker explains what IPv6 is, and how to ensure your business is ready for the move from IPv4.

IPv6: Your Questions Answered!

What is an IP address and why do we need to change to IPv6?

An IP address is the unique identifier for each computer on a network (or the internet). It’s like a postal address to send a letter through the mail, and computers use an IP address to send data to another device over a network.

‘IP’ stands for ‘Internet Protocol’ and forms part of the standard TCP/IP, or Transmission Control Protocol/Internet Protocol, that most broadband-enabled computers use to communicate.

There are currently two standards for IP addresses: IPv4 and IPv6. The most common, and older, one of these two is IPv4 and you will have probably seen such an address in the form of X.X.X.X (e.g.

IPv6 is the new standard that is being brought in to replace IPv4. IPv6 has been around for a number of years already but has only started to gain momentum as the IPv4 addresses have almost run out.

It has a number of technical advantages over IPv4 but the main reason for the change is the massive increase in the number of addresses available. The increase in address space is due to IPv4 using a 32-bit addressing system while IPv6 uses a 128-bit system so an IPv6 address looks very different. Usually it is in the form of 2001:cdba:0000:0000:0000:0000:3257:9652. Sometimes parts of an IPv6 address that contain all zeros are often omitted to save space, leaving a colon separator to mark the gap, as in 2001:cdba::3257:9652.

I run a small business, how do I know if my internet connection is IPv6 enabled?

You can run a quick test to see if the device you are using is IPv6-enabled by going to http://www.test-ipv6.com. This site is especially helpful because it will tell you how prepared your ISP is for IPv6. You can use the test results when talking to your ISP about its plans for IPv6 (and also to check their readiness claims).

Another excellent resource for checking whether you can reach IPv6 enabled sites from your business network is the OpenDNS sandbox. If you aren’t ready to convert your entire network to IPv6 just yet then you can setup up an account with an IPv6 tunnelling provider (some ISPs do all this for you anyway) and then use OpenDNS sandbox to check that you can reach your website via IPv6. Best of all, it’s a free service!

OK, so it says that I’m IPv6-ready, but what does that mean?

There are two types of ‘IPv6-ready’ that you might get from the test.

  • The first is for websites that are running on both IPv4 and IPv6 (which is the majority at the moment)
  • The second is just for websites that are running exclusively on IPv6.

The first is the most common, and don’t panic it is absolutely fine for the moment. It means that you can browse the internet using IPv4, but when you need to connect to an IPv6 IP address it does this by going through (known as ‘tunnelling’) an existing IPv4 gateway run by your ISP, rather than directly from your computer.

The second is where your ISP assigns an IPv6 address along with your IPv4 address (dual stack). This way, if you need to access an IPv6 website you go directly from your computer as you do for the majority of websites at the moment that are still running IPv4. It also means that you can access domain names which just use an IPv6 address and don’t run on IPv4 at all.

As ISPs are moving towards true IPv6 support I recommend you make sure your next router purchase (or if your ISP supplies a router) has native IPv6 support so that you can take advantage of it once it is available.

I’m looking at a new ISP, what questions should I ask them about IPv6?

If you’re changing ISP then it’s worthwhile checking to make sure it has thought about IPv6 and has it setup so that you can use it natively.

I’d recommend you ask the questions below.

  • How long have you been providing IPv6 access to customers?
  • What percentage of your customers are currently using IPv6?
  • Who do you have peering relationships with (i.e. where your ISP interconnects with other networks) that support IPv6?
  • Are these peer relationships native or tunnelled?
  • Do you offer your customers native (or dual stack) IPv6 or tunnelled?
  • Will my IPv6 traffic be native throughout your entire network or will there be areas of IPv6 to IPv4 tunnelling?

You’re looking for an ISP that has native IPv6 through-out the network, has native IPv6 peering relationships and offers dual-stack IPv4/IPv6 to you as a customer.

So, all that sounds great but is there a specific date when everything needs to be IPv6?

There is no specific date when everything must be upgraded to IPv6 (although some organisations have already identified target dates for their own IPv6 implementation). It’s expected that IPv4-only websites and networks will exist for quite a few more years but as IPv4 IP addresses run out, more will move to being IPv6-only.

IPv6 has been around for a long time already and was always designed to run alongside IPv4 for a transition period. In the last few years, with the dwindling number of IPv4 addresses available, there has an increase in the number of IPv6-only networks. The majority of these have been in developing nations (e.g. China has been predominately IPv6 for years) as they have had an explosion of internet users and nowhere near enough IPv4 addresses for them all.

Won’t IPv6 addresses run out eventually as well?

It is theoretically possible that very far into the future that we will run out of IPv6 address space but the numbers are so enormous that it is unlikely to happen anytime soon.

IPv6 was designed to support a mass adoption of IPv6 enabled devices from household appliances to cars; in total it provides roughly 340,000,000,000,000,000,000,000,000,000,000,000,000 unique addresses which to put it into perspective is 480,000,000,000,000,000,000,000,000,000 IPv6 addresses for every single one of the 7 billion people on the planet. Enough for now I think.

For more information about IPv6 and how to switch from IPv4, download the white paper, IPv6: A Primer

This article was written by David Barker, founder and technical director of 4D Data Centres.

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