Modern Software Experience


24 hours of IPv6

World IPv6 Day Logo

World IPv6 Day

2010 Jun 8 is World IPv6 Day. World IPv6 Day is an event organised by the Internet Society. For 24 hours, major web sites and Internet Service Providers will enable IPv6. That includes such familiar names as Google, Yahoo! and FaceBook.


Most of the Internet currently uses Internet Protocol 4, IPv4 for short. Internet Protocol 6 (IPv6) is its successor. There is no IPv5.

Little-Known Secret

The Little-Known Secret of World IPv6 Day is that many of these organisations aren't suddenly enabling IPv6, nor are they turning it off once the day is over. Many organisation of these organisations are already using both IPv4 and IPv6. All they are really doing is making a lot of noise, so that you become aware that IPv6 exists, that the world is going to switch to it, and that it works just fine.

Well, it will work will fine for most of us. During World IPv6 Day, some people may notice that IPv6 does not work for them, but they should not experience any problem; when their IPv6 connection does not work, their system should automatically fall back to IP4.

quad-A record

Technically, most of the participating sites already support IPv6, and you can connect to these sites using IPv6 at any time, not only on World IPv6 Day. For example, you can connect to Google over IPv6 by surfing to In fact, if your ISP supports it, you can simply surf to, and be using IPv6 to do so.

All that most of the participating sites they will doing on World IPv6 Day is publish an AAAA-record (quad-A record) in addition to their already existing A-record.
The A-record and AAA-record are record types used in the Domain Name System (DNS). The A-record is for IPv4, the AAAA-record is for IPv6. The A-record maps the domain name to an IPv4 address The AAA-record maps the domain name to an IPv6 address 2001:4860:0000:1001:0000:0000:0000:0068 (which may be abbreviated to 2001:4860::1001:0:0:0:68).

The A-record is already in the directory. For World IPv6 Day, the AAAA-record is added. That's all that's really happening; an IPv6 address is added to the already existing directory listing. You need that address to connect using IPv6, and for many users that is the only thing they still need, because everything else they are using is IPv6-ready already.
One purpose of World IPv6 Day is to make you aware that you can use IPv6. The other purpose is send a wake-up call to users and ISPs that aren't IPv6-ready yet, that they should do something about it. IPv4 simply doesn't cut it anymore.

Most of the Internet is still using IPv4 while IPv6 is the current protocol. The Internet is running on a legacy protocol.


An IPv4 address consists of four 8-bit numbers. That is 32 bits in total, and 32 bits allow for 2^32 = 4.294.967.296 unique addresses. You might think that some 4,3 milliard addresses is enough, after all it allows about a thousand addresses per living adult. However, it isn't that simple. IP addresses are handed out in chunks, and we've run out of chunks. The Internet Corporation for Assigned Names and Numbers (ICANN) announced on 2011 Feb 3 that it ran out of IPv4 addresses.

That immediately explains why we need IPv6. An IPv6 address consists of eight 16-bit numbers. That is 128 bits in total and 128 bits allow for 2^128 = 340.282.366.920.938.463.463.374.607.431.768.211.456 unique addresses. That is more than 340 sextillion addresses, more than plenty for the foreseeable future.
There are other differences between IPv4 and IPv6, but it is the limited number of addresses supported by IPv4 that makes it necessary to move to IPv6.

IPv6 has been around for more than a dozen years already. The IPv6 standard was published in 1998. Today, IPv6 is supported by most operating systems and network equipment. Most of the Internet is still using IPv4 while IPv6 is the current protocol. The Internet is running on a legacy protocol.

IPv6 support

Windows 2000 supports IPv6 through the IP6v6 Technology Preview. From the release of Windows XP in 2001 onwards, support for IPv6 is a standard part of Windows.

Mac OS X supports IPv6 since version 10.2 Jaguar, released in 2002.

Opera supports IPv6 since version 7.2 released in 2003, Firefox support IPv6 since version 1.5 released in 2005, Internet Explorer has full IPv6 support since version 7 released in 2006, and Google Chrome has supported IPv6 since its introduction in 2008.

joining in

what you need

You do not need to do anything. Whether your systems are IPv6-ready or not, you should not notice anything. If your set-up supports IPv4 only, it will continue to use IPv4. If your set-up support IPv6 too, then it will notice the availability of IPv6, and use that instead. Either way, things should continue to work as usual.

You need not worry about it and do not need to do a thing, but the point of World IPv6 Day is to make sure that you can use IPv6, so it would be nice to make sure that your set-up is IPv6-ready.


There are a few things you need to use IPv6, but even if you have all of them, to access Internet sites over IPv6, your ISP needs to support it too. Many ISP already support IPv6, but do not enable by default. My ISP, XS4ALL, supports IPv6. However, to start using it, I had to login in and activate IPv6 support for my account. It's jus a matter of clicking the Activate IPv6 button. Once I had done so, my account overview showed both an IPv4 and an IPv6 address.


The second step is to configure your router for IPv6. My ISP has been supporting IPv6 for several years already, and I got a new router from my ISP not much more than a year ago. so I was surprised to find that the router they provided is not IPv6-ready. XS4ALL actually has a Wiki with IPv6 configuration instructions for different router makes and models, but the model they provided me with is not listed in there. I did the only thing I could do; after their tech support confirmed that my current router does not support IPv6, I asked for another model. I'll probaby receive it this week, but after World IPv6 Day.

If your router is IPv6-ready, its IPv6 support is probably still not enabled by default. How you enable IPv6 support depends on the make and model. Nowadays, most routers have a user-friendly web interface that make it easy to change settings. Moreover, many ISPs provide how-to instructions for all the routers they provide to their clients. Still, meddling with your router settings is a great way to mess up your connection, so you should proceed with some caution.

operating system

Once both you're ISP and router support IPv6, you have an IPv6 connection to the Internet. All that remains is making sure your computer takes advantage of it. Unless you have a truly ancient desktop computer and browser, it supports IPv6 already. Moreover, with any reasonably modern operating system, network configuration is largely automatic.
If you do have problems getting it to work, your ISP's helpdesk is probably the best place to turn to, although perhaps not on World IPv6 Day itself…

IPv6 problem fix

A few people may discover that their set-up supports IPv6, but that their IPv6 connection is unreliable. Discovering that and then resolving it is a major purpose of World IPv6 Day. However, resolving the issue may take time. You need to discover what is going wrong where. When you figure the problem is with your ISP, there isn't much you can do but wait for them to fix it. Meanwhile, you probably want your connectivity issues solved immediately.

The fix is simple. When both IPv4 and IPv6 are available, systems normally prefer IPv6 over IPv4. However, if you encounter problems using IPv6, you probably want to change that around; change your system settings to prefer IPv4 over IPv6. That's all you need to do.
Completely disabling IPv6 support will work as well, but is not recommended. Your system should support IPv6. You should not disable IPv6, but work towards the day that you will turn of the legacy IPv4 support.
Microsoft has published a fix that will make Windows prefer IPv4 instead of IPv6, and switch back to preferring IPv6 once World IPv6 Day is over.


World IPv6 Day

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