A date to remember for me: On 15th January 2016 I contacted my web server at home running Owncloud and Selfoss for the first time over IPv6. From an end user's point of view no difference is visible at all but from a technical point of view it's a great "first time" for me, made even sweeter by the fact that my PC was not connected to another IPv6-enabled fixed line but connected via tethering to a smartphone with dual-stack IPv4v6 cellular connectivity.
The Thing With Dynamic IPv6 Addresses for Servers
And it's been a bit of a struggle to put together, this IPv6 stuff is not as straight forward as I hoped it would be. For a crash course I wrote back in 2009 have a look, here, here, here and here. The major challenge that I had to overcome for this to happen is to find a dynamic DNS service that can handle not only dynamic IPv4 addresses but also dynamic IPv6. Noip.com, where I host my domain and where I use the dynamic DNS service can handle IPv6 addresses for my domain but only static entries. The response to a support question how to do dynamic IPv6 addresses with them resulted in the little informative answer that they are working on it but no date has been announced by when this will be available. Hm, looking at their record, they seem to be working on IPv6 already since 2011 so I won't get my hopes up that this will happen soon. Is it really that difficult? Shame on you!
O.k., another dynamic DNS service I use is afraid.org and they do offer dynamic DNS with IPv6. Unfortunately, they have a DNS entry time to live (TTL) for IPv6 of 3600 seconds, i.e. 1 hour. This is much too long for my purposes as my IPv6 prefix changes once a day and any change must be propagated as quickly as possible and not only after an hour in the worst case. They offer a lower TTL with a paid account, but their idea and my idea of how much this may cost are too far apart. I've found a couple of other dynamic IPv6 services but they were also not suitable for me because they also had TTLs that were too long for my purpose.
One option I found that didn't have this restriction is dynv6.com. Their service is free and they do offer IPv4 and IPv6 dynamic DNS with a TTL of 1 minute but only for their own domain. Not an option for me either, I want to be reachable via my own domain. Kind of a deadlock situation…
But here's how I finally go it to work: The Domain Name System has a forwarding mechanism, the "Canonical Name Record" (CNAME). By using this mechanism, I can forward DNS queries for my domain that is hosted at noip.com (let's say it's called www.martin.com) to my subdomain at dynv6.com (let's say my domain there is called martin.dynv6.com). So instead of updating the DNS entry for www.martin.com when my IPv6 address changes once a day I can now update martin.dynv6.com which has a TTL of 1 minute while the CNAME forwarding at noip.com from www.martin.com to martin.dynv6.com in the DNS system is static and remains unchanged.
As a result the web page name in the browser remains "www.martin.com" but I can use my dynamic IPv6 record at dynv6.com where customer specific domains are not offered. Not ideal but it will do until NO-IP.com gets their act together.