IPv6 basics: Getting started with IPv6
Like it or lump it, you're going to need to add IPv6 to your network. Here's how to start.
As I write this in late October 2010, the Internet is officially down to less than 5% of the possible IPv4 addresses. The bad news? It's actually worse than that, according to the real-time IPv4 Address Report, we're down to 4%. At this rate, local ISPs and businesses won't be able to get new IP addresses after January 2012.
That doesn't mean that Internet addresses won't be available. They will be. But, as with good domain names, you can expect to start paying a pretty penny for your IP (Internet Protocol) addresses. This won't matter so long as you or your business doesn't expand or move, but when you do, as time goes on you can expect to pay progressively more for your new addresses.
"Imagine the IPv4 address space is [a] 1.6-inch square. In that case, the IPv6 address space would be represented by a square the size of the solar system."
When the Internet began, IPv4's possible 32-bit 4.3 billion addresses looked like more than enough. We didn't see mobile devices coming or predict that people would start carrying two or three IP devices -- smartphone, laptop, tablet, MP3 player, etc. -- at once. We could blame Vint Cerf for this vision failure, but it's too late to play the blame game. It's time to start working on the problem.
Let me point out that although that the IPv4 shortage isn't an emergency, it's still an issue that businesses need to start addressing now. Tried and true technologies like Network Address Translation (NAT) will not be able to save us from the growing Internet address shortage. Eventually you will need to be running IPv6.
IPv6 addresses explained
So what does IPv6 bring to the table? Well, for one thing, instead of a mere 4.3 billion possible addresses, IPv6, with its 128-bit address space can have, deep breath, "340,282,366,920,938,463,463,374,607,431,768,211,456." Or, as one person put it: "imagine the IPv4 address space is [a] 1.6-inch square. In that case, the IPv6 address space would be represented by a square the size of the solar system." In short, we're not going to run out of IPv6 addresses any time soon.
With IPv6, every device, and I mean every last one, can have its own unique IPV6 address.
IPv6 addresses are denoted by eight groups of hexadecimal quartets separated by colons in between them. IPv6 networks themselves use Classless Inter-Domain Routing (CIDR) notation. Therefore a network or subnet using IPv6 must be a contiguous group of IPv6 addresses whose size must be a power of two.
These addresses can look quite intimidating at first. For example, 2001:cdba:0000:0000:0000:0000:1956:2010, is a valid IPv6 address. You won't usually need to write out so many zeros though.
Any four-digit group of zeros within an IPv6 address can be reduced to a single zero or altogether omitted. So, the following are all valid, and indeed, functionally identical addresses:
There a few other rules you should know about IPv6 addressing. First, while you can dump in-line zeros, you can only do so if it contains nothing but zeros. So, for instance, if instead of 1956 I had 0006, I'd still need to include those extra zeros. Second, you can use the double colon only once in an address.
You should also know that, just like in IPv4, there is a loopback address that points to the local machine. The loopback address for any IPv4-enabled device is 127.0.0.1.
Like IPv4, there is a designated loopback address for IPv6:
You'll be glad to know that you suppress all those zeros and you end up with ::1. And, just as in IPv4, the loopback address can be useful for working out computer problems.
With any luck, you'll never need to write any long IPv6 address out or manually assign one. With an IPv6 router or switch on your network, it will take care of automatically assigning addresses.
You'll also never need to worry about assigning subnet masks again. While IPv6 also uses subnets, they're part of the address. To be exact, the first 48 characters in IPv6 are the network prefix. The next 16 characters, which more often than not are zeros, are the subnet ID. The last 64 characters are the interface identifier.
Unlike IPv4, where you always needed to use subnets to help manage routing, subnetting is optional in an IPv6 LAN. I've often seen them used for management purposes. For example, you can set up all of Building 4 in one subnet and all of Accounting in another, and so on.
Broadly speaking there are three kinds of IPv6 addresses:
1. Unicast addresses A Unicast address acts as an identifier for a single interface. This is the equivalent to the IPv4 address your computer is using at this very moment to identify itself as a unique PC on your local network. The point of Unicast is to make it easier to manage Internet addressing and routing.
2. Multicast addresses A Multicast address acts as an identifier for multiple network interfaces even if they belong to different nodes. So, for instance, any IPv6 packet sent to the Multicast address: FF02:0:0:0:0:0:0:2 is sent to all routers on the local network. Multicast is most commonly used for sending signals to a given group of systems or for broadcasting video or audio to multiple computers at once.
3. Anycast addresses In Anycast, a packet is delivered to the nearest, in terms of routing distance, of multiple interfaces. So, for instance, if you sent out a packet to an anycast address, your router or switch will send it to the closest possible device.
Implementing IPv6 in your office
So that's all well and good, but what do you need to do to start using IPv6? Well, on your PCs, you might not need to do anything. Windows, starting with Vista, turned IPv6 on by default. Windows didn't do anything with it mind you, but it was on.
I can't think of a single significant desktop operating system that doesn't have IPv6 support baked in. Mac OS X and Linux. The same is true of server operating systems: Windows Server 2008; Solaris, Red Hat Enterprise Linux (RHEL), Ubuntu and all the others.
The real trick is getting network equipment that supports IPv6. That may sound odd. I certainly find it so. While enterprise level network switches, such as the Cisco Catalyst series and Juniper Networks EX Series switches do a fine job of supporting IPv6, small business and home products often don't support it or do a lousy job of it.
If you're running a small business or want to get ahead of the IPv6 curve at home, do not assume that the switches and routers in your price range will have IPv6. Check. Then, even if the company states that it does, I hate to say this, but you're going to need to check again by trying it out.
I've found much so-called IPv6 compliant equipment really wasn't when push came to shove.
Making the IPv6 Internet connection
OK, your PCs, servers, and what-have-you are all running IPv6 and you want to connect to the IPv6 Internet, now what?
First, you need your ISP to support it. Not all do. A few, like Hurricane Electric support IPv6 at their core and everywhere else. Others have deployed it only on a limited number of routers. What happens here is that your IPv6 traffic is being backhauled via a "tunnel" through the IPv4 Internet to a limited number of switches with IPv6 connectivity. That's not likely to be either fast or robust.
I'm not crazy about those who support IPv6 only with tunnels. What this tells me is that sometime down the road, when the ISP moves to full dual IPv4/IPv6 protocol support, I'll need to change my edge networking setup yet again. That's no win in my book.
And, there are a few ISPs that still haven't deployed it anywhere. If your ISP or Web host is one of the latter, I can't recommend strongly enough that you find another provider. They're not investing in their technology base, and that's a bad sign.
So what you really want is a service provider that provides dual-protocol "native" IPv6 connectivity This should not cost you any more money. Ironically, because IPv6 has been so slow to take off, the ISPs have never been able to convince customers it's worth extra money and, in turn, this has delayed their IPv6 backbone rollout.
When choosing an IPv6 ISP you should consult the SixXS IPv6 deployment page. Another useful site is the IPv6 BGP Weathermap. If you look under "Top 25 Transit/Upstream AS numbers in the routing table," you'll see the top ISPs that are actively supporting IPv6.
Of course, you'll also need to be able to work with the IPv4 Internet for many years to come.
Fortunately, there are many technologies that will let IPv6 and IPv4 co-exist peacefully.
Once you've decided to make the jump, the exact details of how you'll make the leap depends on your ISP. It won't be easy, but in the long run it will be necessary. Good luck!