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Recent news reports about the transition to IPv6 have many people concerned. For the average consumer, I believe there's little if any immediate impact.

In my local free paper, I read a headline, "Internet full, please try later..." The article basically said they have run out of IPv4 numbers and, to quote directly, "Consumers using older software such as Windows XP and many household broadband modems cannot read IPv6 ... and websites with new-style addresses may not be accessible to many users." What do you know about this?

At work, we still have a couple of Windows 9.x and Windows ME computers. I also have an older game machine with Windows 98. Will all three still work when IPv6 arrives?

There were a few news reports in recent weeks describing how the internet is running out of the addresses used to identify individual computers. As a result, the internet is moving to a new addressing scheme that will allow substantially more connections.

The headlines that I keep seeing are all pretty sensationalistic.

The reality, I believe, is a lot more boring and doesn't make for gripping news articles.

The average consumer does not need to worry. At least, not for a long time.

IP? v4? v6?

First, let's remove some mystery. "IP" is the IP in TCP/IP, and stands for Internet Protocol - the basic language of machines and devices communicating with each other. V4 simply indicates that this is the fourth version of the protocol.

In IPv4, each device connected to a network is uniquely identified by a number between zero and four billion. OK, not exactly zero and four billion, because some numbers are reserved, but you get the idea.

"In short, I truly believe that the average consumer won't notice much for a very long time."

That's the number that you often see expressed as four smaller numbers separated by periods. For example, the IP address of the server hosting Ask Leo! on the internet is today I say today because it's been different in the past and could change tomorrow. That's why you use the address to get to the site, not the IP address.

There was a time when four billion seemed like more than enough, yet current estimates are that we will run out sometime in 2012.

As a result, IPv6 changes the addressing scheme to be four times bigger. No, not four times four billion, but rather four billion raised to the fourth power.

Put another way, with IPv6, we could theoretically have 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses on the internet.

What happens when we run out of IPv4?

Not a lot, really. If we run out, then it becomes more difficult to put more machines directly on the internet. All of the existing machines, servers, and services could keep on running as they did before, and more machines could always be connected via NAT routers, as you probably do today.

There just wouldn't be any room to add more directly to the internet. That's where some of these "The Internet Is Full" headlines have come from.

So, what that means to you is ... well, not much. For the most part, things will just keep working even after we run out.

The internet and the services you use today will continue to support IPv4 for many, many years. The lack of IPv4 addresses simply makes it more difficult to add new resources to the internet that everyone can reach.

The Transition to IPv6

It's important to realize that switching to IPv6 is a process, not an event. In fact, it's a process that has been underway for years already; one that will continue for many more years into the future.

The majority of the internet's infrastructure can already handle both IPv4 and IPv6 simultaneously.

Most of the work is left at the endpoints - the servers that you find on the web, and the machines like yours and mine that use them.

As you've seen, most new operating systems are ready for IPv6. Windows XP, Vista, and Windows 7 all either include or have available IPv6 networking support. Most current versions of Linux and Mac OS also support IPv6.

The largest remaining piece of work is in between: the millions of modems and routers in homes and businesses that aren't quite ready for IPv6, and the actual assignment of IPv6 addresses in addition to IPv4. That'll take some time.

This summer, several of the major internet services are getting together to test IPv6 just for that reason. World IPv6 day is a test where sites like Google will support IPv6 for 24 hours as a test.

Your Computer Won't Break

If you can't upgrade your computer or your internet connection, your machine won't break ... at least, not for a while.

There are a hand full of scenarios where it could:

  • The remote resource became an IPv6 only resource. If someday decided to release it's IPv4 address and only have an IPv6 address, then IPv6 would be required to access it. As you can imagine, that wouldn't be a very smart move on the part of The vast majority of the sites and services you use today will continue to use IPv4 in addition to IPv6 as long as is possible.

  • Some equipment between your computer and whatever site you're attempting to access decides to go IPv6 only and no longer carry IPv4 traffic. This is actually pretty unlikely until the very end of IPv4 use, as it'll break a lot of communication attempts. Again, the equipment that carries traffic around the internet will continue to support IPv4 as long as possible.

  • Your equipment is IPv6 capable, but misconfigured.

In short, I truly believe that the average consumer won't notice much for a very long time. Things will continue to work. Eventually, your ISP will give you an upgraded modem that will support IPv6. The next router switch or hub that you purchase will also very likely support IPv6 as well.


Someday, the majority of sites and services that you use will all support IPv6 in addition to IPv4.

Someday, when setting up a new internet connection, your ISP will just give you IPv6 equipment and an IPv6 address.

Someday, your ISP will ask you to upgrade the modem or router on your existing internet connection.

Someday, websites and the internet will stop supporting IPv4.

It's only when that last someday happens that your old devices that can't support IPv6 will start to have problems.

And that day is years away.

Article C4742 - February 13, 2011 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Mark Shepherd
February 14, 2011 5:42 AM

Leo, Typo alert: "Most of the work is left at the endpoints - the servers that you find on the web, and the machines like yours and mind that use them." Shouldn't it be "mine"?

A good place to test your ability to handle IPv6 is:

For more info than you need to know about IPv6:

And of course you can also try hitting : -If it shows you the normal google home page absolutly everything from your machine to googles servers is running with IPv6 enabled. And that can change day to day.

February 15, 2011 8:26 AM

I don't necessarily want to start an anti-media rant, but when Leo mentions "sensationalistic", I believe that's exactly what this is. Anyone remember the Y2K bug...or rather, lack of one? Yes, the computer date thing was a very real issue but human nature (and flames fanned by the media) blew it completely out of proportion. My boss does this to me about once a year or two. He reads an article about a brand new virus and then prints it out on paper and puts it on my desk. I then have to explain to him (in a professional, polite manner) that the virus is not a threat for us because we do regular updates, have a firewall, and all other bases covered. It's typically a front-page Yahoo article or something of that nature and I'd be willing to bet two things are true: 1) there's just nothing more for Yahoo to report on that day and 2) they haven't run the "latest virus" related article lately, so BLAM, it's posted that day and my boss (and many others) get spooked because they don't know any better.

...makes you wonder just how much sway the media can have on other topics most humans don't know anything about, oh...I don't know....economics, politics, and health (H1N1 anyone?)

Dang...I guess I did turn this into an anti-media rant.

February 15, 2011 8:41 AM

So... the gist of this is that by the time IPv6 becomes any real kind of issue, XP will have long since gone the way of Windows 3.1?

I believe so. But XP supports IPv6 - I've gotten questions from people running Windows 98, which will likely never run IPv6 natively.

February 15, 2011 11:30 AM

I have to agree that the media seems intent on "grabbing headlines" to make themselves look good which has a tendancy to confuse and mislead those they write for. Will they never learn?

Steve Auerbach
February 15, 2011 11:45 AM

Is IPV6 really version six or does the six refer to the six hex "digits" that comprise the address and the four refer to the four that compress current addresses?

It is indeed version 6. The 4 and 6 don't refer to any characteristic of the address. Quoting Wikipedia: "Version numbers 0 through 3 were development versions of IPv4 used between 1977 and 1979. Version number 5 was used by the Internet Stream Protocol, an experimental streaming protocol."

February 15, 2011 12:56 PM

Of what use is the IP helper service? It's supposed to enable IPv6 connectivity over an IPv4 network. Using the links given above it fails miserably.

Glenn P.
February 15, 2011 3:26 PM

Two Comments, Leo.

First: "Some equipment between your computer and whatever site you're attempting to access decides to go IPv6 only and no longer carry IPv4 traffic."  ...which the good 'ole Internet promptly interprets as Damage, and routes around! Silly ole Leo!      :)

Second: "Someday, websites and the internet will stop supporting IPv4. It's only when that last someday happens that your old devices that can't support IPv6 will start to have problems. And that day is years away."  ...Folks, it's your ISP in most cases that's responsible for delivering the Web to your browser. As long as your ISP is able to deliver the Internet to your computer -- or as long as your computer is able to interface successfully with your ISP to receive Internet access -- what "standard(s)" are involved in the transaction matters not one whit. Heck, I can still browse the Internet on my Commodore-128 using Lynx via a Unix shell account on my local ISP if I want/need to, and I still occasionally use Unix Pine via my C128 for my E-Mail!!!

IPv6? Heck, my C128 doesn't even know what IPv4 is!!!

February 15, 2011 6:44 PM

First, to answer Steve's question, yes the "6" is really Version 6 (since "5" had been assigned o something else), but nearly was version 7. Just Google "IPV5" and settle down with an adult beverage for a trip through IETF memory lane.

Some folks have been tempted to uninstall IPV6 from their machines, thinking that that will improve networking performance, save space, etc. It turns out that 1) it's harder than it looks, and 2) it's not as good an idea as it seems. You can Google around to find out why, but save some time (and probable grief) and just go with the IPV6 flow.

February 23, 2011 3:14 AM

so much for speedy FIOS
Test with IPv4 DNS record ok (0.437s) using ipv4
Test with IPv6 DNS record timeout (15.031s)
Test with Dual Stack DNS record ok (0.266s) using ipv4
Test IPv4 without DNS ok (0.266s) using ipv4
Test IPv6 without DNS timeout (15.031s)
Test IPv6 large packet timeout (15.032s)
Test if your ISP's DNS server uses IPv6 bad (0.343s)
from website

March 11, 2011 8:04 PM

Why is it that the number of IP addresses required wasn't better planned for? I hardly know anything about IP but saying IPv4 could only handle 4billion addresses seems like a massive oversite failure. There are 6.5billion people in the world, and many people have more than one IP address.

Because when IPv4 was designed no one ever believed it would actually be used for a public, global network, or that there would be so many individual devices.

May 29, 2012 7:24 PM

A year later, the test still fails on FIOS(or I am doing something wrong). I will test Cox at work, tomorrow. In the network connections, I simply found the listing for IPv6 and Ipv4 and unchecked IPv4 and could not connect to any website.

It's much too soon to expect any more than a handful of websites to work with IPv6. IPv4 will work for a long, long time. I wouldn't worry about it.
May 31, 2012 3:33 AM

The same Ipv6 test website failed on Cox@work. Cox is a local cable company, similar to comcast.

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