A protocol is nothing if never used. Well, okay, maybe it can be a joke. Maybe. Okay, so that's not really a protocol. Evil Bit jokes are still positive net karma, right?
Likewise, IPv6 is pretty much useless if it is never used. I can assign the addresses all I please but ultimately if all I do is ping my desktop that sits "behind NAT" with it then for the most part the effort was wasted.
My server runs CentOS 5.2, my desktop runs Gentoo, my laptop Debian, my router Debian, my windows desktop Vista (dual boot Server 2008), and the Vista box also has three instances of OpenBSD running within VMWare.
I've got a pretty good testbed to see just what does/doesn't support IPv6, in terms of everything general web browsing to random system daemons to whatever end user programs you have a desire to run. So, I put together a small bit of info concerning what handles IPv6 perfectly, what is kind of broken, and what just looks at it with a mystified look on its face.
So to start:
Operating Systems
Windows
As far as I know, the first IPv6 stack was available for Windows 2000 via a separate download. XP bundled it by default, but left it uninstalled. Vista has the IPv6 stack enabled by default.
Linux
Got a pretty new IPv6 stack with 2.6. Had a working stack in 2.4. I'm pretty sure 2.2 had a functional stack too, as did 2.0. Don't quote me on that.
OpenBSD
Has supported IPv6 since 2.7.
Services/Servers
Apache
Apache has support IPv6 ever since the 2.0 release. Every component of apache that I tested supported IPv6 just fine, from general web page serving to SSL to proxies. Considering how much of the web is still on 1.3, all of those hosts will have to be upgraded to 2.0+ before a much wider IPv6 web base is available.
IIS
IIS (the Microsoft webserver) has supported IPv6 from their 6.0 release, also known as Server 2003. Most places use at least 2003 on their servers, the era of Win2k webservers kind of died out with Code Red and all of those other worms.
MySQL
Just kind of sits and looks at IPv6 like it has no clue what it is. Which is actually entirely true. Boo.
PostgreSQL
Talks happily with IPv6. At least I think. I'm too lazy to start my local copy and check. Their page on the matter isn't what one would call descriptive. No clue when this support was added.
MSSQL
Supported since their 2005 release.
Oracle
Offically supported as of 2006.
Samba
Supported as of the 3.2 release, which was actually just on June 1st of this year.
Windows SMB/CIFS
Supported with XP and onward. Probably Win2000 too.
So the servers are looking pretty good. Unless you run MySQL, which is pretty much everyone. Boo.
At a minimum, we can serve any content over HTTP just fine, and we can access most database just fine too, unless your name starts with a "My" and ends with a "SQL."
End-user programs
Mozilla Suite (and Firefox, Thunderbird, Seamonkey and friends)
Native IPv6 support, ever since the year 2000. Still has some work to be done according to the meta bug, but pretty much all of those bugs are on random operating systems that don't adversely change your ability to connect to IPv6 enabled sites.
Internet Explorer
Supported IPv6 ever since 4.0, once you applied a patch from their research division. Likewise real native support was probably with 5.0, if not it was by 6.0.
Outlook
Supported as of Outlook 2007.
Kopete
Supported. The KDE project has traces of IPv6 development starting around 1999. As far as I can tell, IPv6 is natively supported in every program in 3.5.
Pidgin
Supported. Not clue as of when due to the GAIM --> Pidgin name change, and I'm far too lazy to figure that out.
MSN Messenger, AIM, ICQ and friends
Who cares? (Likely not supported, though I doubt the client is the blocker in these cases.)
PuTTY
Supported since '04.
OpenSSH(d)
Supported. Probably since forever. Go OpenSSH.
irssi
Supported!
mIRC
Not supported without loading a third-party DLL. mIRC sucks anyway.
X-Chat
Supported.... on Windows since '03, *nix and friends likely even earlier.
I could go on and on and on. I won't, because I have no desire to list hundreds of thousands of software packages and their relative IPv6 states. Plus I'm getting tired and this entire post was spontaneous. Not too bad for 30 minutes of google.
But for the most part, we've got a great picture. Every operating system, browser, and web server supports IPv6 and supports it fantastically well. Nearly every program on *nix supports IPv6 and has for quite some time, and most of the big name Windows programs support IPv6 as well.
Not mentioned here was DNS, but the protocol has had support for it since (just about) forever and now that we have AAAA records for the root servers in the public DNS, DNS is good to go with IPv6 from start to finish.
Now we just have to work on the ISPs and home grade routers...
Footnote: one of the comments I got on my initial IPv6 entry was someone reporting success in integrating their LAN with IPv6. While I'm glad to hear it, I'm even more glad that when I got the "unapproved comment has been posted" notification e-mail, the corresponding IP address was a v6 address. The second I had IPv6 up and running on my server, I threw in AAAA records for pretty much everything. If I had to guess, they didn't even know they were using IPv6 to view this blog and post the comment - which is exactly the goal.
Not too long ago, after reading yet another "the internet is dying! We're running out of address space and it's all coming by November 2010 according to Cisco!" I realized that, "hey waitaminute - that's just about two years from now. That's... soon."
So I setup IPv6 for the machines I own. I still depend on IPv4 simply due to IPv6 not being available... well, most anywhere. At least not natively.
A big part of the reason that we don't have IPv6 in more places is because... well, circular dependency here, but because it isn't around. I can't plug my laptop into any other ISP's line and use IPv6 natively, and even if I could, the chances of the average home grade router working with it is about two.
Out of thousands.
So to get around this, IPv6 in IPv4 tunnels are used. They do exactly what their name implies: tunnels IPv6 data within IPv4 packets. The downsides to IPv6 tunneling are latency/overhead and... your ability to keep your IP addresses. If you don't have native IPv6, then your current hosting provider or ISP won't be the one giving it to you - meaning you get to get the IPs from a third party company. When your hosting provider or ISP turns IPv6 on, what are the chances that you'll be able to reassign entire blocks of IPv6 address space? Probably not too great. If you've got Comcast as your home ISP, I don't think that your tunnel broker is going to happily move your address blocks over to Comcast's control - at all.
While the latter point is generally a deal breaker for a lot of people, in the long run, I don't care. IP address reassignment happens all the time. There's no rule stating that you must drop your tunnels once you get native IPv6, and there's no reason why it would be overly problematic or painful either. Simply bring up the native IPv6, change the DNS records, and drop your tunnels a few days later.
With this knowledge in hand, I went poking around the vast area known as the Internet and selected Hurricane Electric's IPv6 Tunnel Broker. What really sold me (for free, that is) on using HE for my tunnel was really twofold: one, their views on IPv6 (which boil down to "we'd really like to be in business when IPv4 is exhausted, so we're going to deploy native IPv6 everywhere, provide a tunnel broker for free for anyone and everyone, and we're going to do it three years before crunch time") and two, the fact that it was free.
In selecting HE, I also got full reverse DNS control, selection of the closest HE router to my server, full control of a /64 subnet and a /48 subnet (by request, which I requested), the possibility of adding three more /64 subnets and three more /48 subnets to my account, and full operating system support (with instructions for setup with linux-net-tools, iproute2, *BSD, OSX, Solaris, Windows XP+, and Cisco).
Not bad for $0. I'm a happy customer (and a potential customer should I ever need colocation/dedicated servers).
I setup my account with HE, logged in, and was presented with simplistic instructions on how to setup my CentOS server.
ip tunnel add he-ipv6 mode sit remote 209.51.161.58 local 64.22.124.36 ttl 255 ip link set he-ipv6 up ip addr add 2001:470:4:b2::2/64 dev he-ipv6 ip route add ::/0 dev he-ipv6
I created a new 'sit' tunnel named 'he-ipv6', with remote endpoint 209.51.161.58 - coming from 64.22.124.36 - and then turned the link up. Easy enough. Then I added my /64 allocation to the newly created tunnel, and pointed the default route through that tunnel.
Wait a minute. That's it? I'm IPv6 enabled already?
[kyle@averageurl ~]$ ping6 ipv6.google.com PING ipv6.google.com(2001:4860:0:1001::68) 56 data bytes 64 bytes from 2001:4860:0:1001::68: icmp_seq=0 ttl=55 time=327 msYup...
From there, I requested a /48 subnet so I could allocate a few full /64 subnets to my house (a /64 for my LAN, wifi, and secondary wifi), brought some more tunnels up, and then from my desktop...
kyle@ksb ~ $ ping6 ipv6.google.com PING ipv6.google.com(2001:4860:0:2001::68) 56 data bytes 64 bytes from 2001:4860:0:2001::68: icmp_seq=1 ttl=54 time=325 ms
And now my desktop is IPv6 enabled. Go ahead, ping6 2001:470:d82b:ffff::2! You'll hit my home desktop. Then ping ::3 - my Vista box. Yup, that's right! My windows box is also on the IPv6 network. :fffe::2 would be my laptop on the wifi. The entire :fffd::0/64 subnet (and corresponding wifi AP) is unused currently, but perhaps once I decide to upgrade my router's software and play with wpa_supplicant that will change.
But why did I do this? What did I gain? Well, for starters, it was really fun to use HE's Looking Glass to run a traceroute to my desktop...
Tracing the route to IPv6 node 2001:470:d82b:ffff::2 from 1 to 30 hops 1 2 ms <1 ms <1 ms 2001:470:0:32::2 2 76 ms 75 ms 75 ms 2001:470:0:35::2 3 103 ms 103 ms 103 ms 2001:470:0:4b::2 4 103 ms 103 ms 103 ms 2001:470:0:8c::2 5 148 ms 148 ms 148 ms 2001:470:4:b2::1 6 234 ms 236 ms 238 ms 2001:470:d82b:ffff::1 7 234 ms 233 ms 233 ms 2001:470:d82b:ffff::2... while it sits behind my IPv4 NAT router. And then my Vista computer, and then my laptop connected to the wifi. Then I got to go take a look at The KAME project and check out the dancing turtle. It turns out that Google's IPv6 site also has an animated logo.
But in the end, I can now access all of my computers from behind NAT, without actually using any NAT - at all. I could drop the IPv4 addresses from some computers and still retain access to them, full access. This may prove to be both a blessing and a curse, but given time, we'll see..
(And yes, I know I shouldn't be using ::1 for my routers, that'll change soon enough.)