Despite IPv6 being announced as the successor of IPv4, at times little is done to give it the chance to be deployed properly. I noticed that most standard Cisco IOSes still don’t support it – No support in the 3560 IP Basic and even IP Services IOS.
Update: 28/01/2012: 3560 does support it, see SDM templates.

Most consumer routers these days also don’t offer support for IPv6 yet (but I suppose firmware updates in the future could solve this, and some high end models are starting to give support).

It does make one wonder: a protocol that has been around for almost 13 years now, clearly designed to counter an address shortage, yet still little is done to help building out infrastructure for it in everyday live. The good news is that Microsoft’s and Apple’s operating systems have IPv6 support by default now, with Linux already supporting it for years, so end-user devices are mostly ready for it. It’s everything between all those end devices that’s the problem (except for Layer 2 switches of course).

A second thing to wonder about is the whole SLAAC/DHCPv6 issue: IPv6 came with this nice StateLess Address Auto Configuration mechanism so every device could find it’s IP address automatically. It even finds the subnet’s gateway. But it doesn’t give a DNS server: for that you need a DHCPv6 server, which, surprise surprise, does not give a gateway.

From a network engineer’s point of view this is somewhat understandable: the gateway is something you need at Layer 3, while DNS can be classified with the rest of the DHCP options (TFTP, NTP,…) under Layer 7 services. But it doesn’t make things easier for an end-user. To date this means that a consumer router will have to run both SLAAC and DHCPv6. There are also differences between how Windows, OSX and Linux treat the information they receive: some operating systems ignore the ‘Managed address configuration’ or ‘Other configuration’ flag, others don’t. Also, most DHCPv6 servers I tested to date did not give the expected results: Cisco’s implementation in their IOSes did not do anything (though the new 15.x IOS may have solved this, or I simply did things wrong), Vyatta’s DHCPv6 server does not get formatted properly in their configuration files and does nothing as well (a known bug still in research). Windows Server 2008 does give a working DHCPv6 server, but it requires a reboot for each change I’ve noticed so far.

All in all, IPv6 still seems to have a long road ahead.