I have serious concerns with IPv6's practicality, even with 6in4 et al. Is trying to implement it just flogging a dead horse?
If somebody comes up with a way to actually get IPv6-only nodes widespread - not just nodes with joint IPv4 and IPv6 machines - then I'll have hope for mainstream IPv6. But while every client and server has to have IPv4 as well to be of any use, then what benefit does having IPv6 connectivity give it?
Yes, the transition is going very very slowly. But I don't think there is a problem. One could argue it's the same with IPv4 addresses as with oil. Eventually, it will get more expensive as it gets more scarce, and people will gradually switch to alternatives.
At a certain moment all the important sites will have adapted IPv6 that it's economical for some users to drop expensive IPv4. Sites will then hurry to go to IPv6 as they lose customers. But I guess there's no need to hurry yet... at least for us IPv4-rich western countries.
* Why do clients - home ADSL users, small offices, wifi hotspots - want to bother with IPv6? It offers them no benefit for at least several years. Everything that's good is IPv4 only, or maybe IPv4 and IPv6. All they need is one external IPv4 - or they can share an upstream IPv4 via carrier-grade NAT, so they needn't bear any "rising cost" of IPv4.
* Why should important sites really bother about IPv6? They already have large IPv4 allocations, and there's endless tricks to make better use of them (they can vhost any HTTP-based service, for a start). Moving to IPv6 will make it easier for startups to get IPs to compete with them. I'm not sure why some of them have offered limited IPv6 access (Facebook's is just a proxy that forwards on the connections via IPv4, it seems), but they don't seem to maintain them well (bit.ly was inaccessible via IPv6 all day; nobody seemed to notice) - I suspect they're mainly "20% time" projects.
* Just how near is the point where it's a good idea to drop IPv4, for clients or servers? There's a lot of legacy networks to shift... more so on the client end than on the server end, which is dominated by a "top 100 sites" or so that could all conceivably add IPv6 support with little effort.
I know what the current state of affairs is. I don't understand why all the "IPv6 is not widely adopted yet so let's rationalize it as if we'll be on IPv4 forever" posts on HN lately. It is a slow, gradual process. If you don't want to worry about it yet then just don't.
Back when 64 bit CPUs were entering the consumer realm, you also had people saying "Man, addresses will take two times as much space and who needs to address that amount of memory? And there are plenty of memory mapping tricks to keep us on 32-bit for a long time"...
The only downside is you need better firewalls.
Which is why I suggested setting up SOCKS as a competitor to NAT, as it lets the client ask the gateway device for an external IP/PORT to do peer-to-peer communications over... without needing to set up IPv6 :-)
