In your letter dated Sun, 3 Jul 2011 07:53:46 +0200 you wrote: >Unfortunately, in the 20% of the time that it's not working, Google has no >idea that the user has a 2002::/16 address. Google only knows, after the >fact, that the user suffered a 20 or 75-second timeout and was not happy. So >it would serve no purpose to avoid serving users that successfully connect >from 2002::/16 addresses; once the AAAA record is handed out, the damage is >done. What Google could do, however, is stop handing out AAAA records to >networks that have significant number of 6to4 users in the future. We're >considering this. I think this clearly illustrates why the IETF should issue a strong statement that no new 6to4 installation should be deplayed and the existing 6to4 users should migrate to other tunneling techniques (if native is not available). The problem with 6to4 is it was rolled out on a relatively large scale when there was essentially no IPv6 content. As a result, the people who had a broken 6to4 setup would only find out when content providers would start adding AAAA records. In other words, it was ticking time bomb. This time bomb has been defused mostly because most operating system now prefer any kind of IPv4 over a 6to4 address. So once again people can have a broken 6to4 setup without noticing it. What worries me is that people will start using 6to4 for bittorrent. Bittorrent will of course completely hide broken setups and worse, it will also hide broken 6to4 relays. So we may end up with a sizable group people who have an IPv6 setup that completely doesn't work. And they don't know it. Which will create all kinds of headaches for IPv6-only content because you have to explain to users that yes, they have an IPv6 address and no, it is not going to work. And all of this, because a few hobbyists are afraid that declaring 6to4 as historic will require them to search a bit harder in the furture for a router that supports 6to4. _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf