On 17/07/2013 19:13, Ignatios Souvatzis wrote: ... > Let me ask one thing... a couple of years ago, when I read the > specification of Teredo, I was quite impressed by the details (If > you accept the premise that you have to work around being jailed > behind an IPv4 NAT) put into the protocol. One detail was that it > is supposed to be lowest priority and so go automatically away > (from the client end) as soon as some configued IPv6 is available > on the link. > > Isn't that how it's implemented?
Yes, but the result is that the host tries to use Teredo preferentially even if the IPv4 path is better; and if the Teredo path is broken the result is user pain (as with 6to4). I think the idea of deprecating Teredo is that now that native IPv6 is a serious option, the costs of Teredo outweigh the benefits,on average. (Unfortunately nobody ever wrote the Teredo equivalent of RFC6343.) Brian