Yes, and Teredo was invented exactly to deal with the issues
raised by 6to4 in a SOHO environment.
Surely there is a better way than that kludge though. Given that NAT
also is a kludge, we really should earnestly consider how to NOT build on
top of it... otherwise, we run the risk of a very nasty stack down the
road. At worst we should be able to encourage firmware updates for those
NAT boxes... radvd works very well. At best the CPE should be
providing v6, perhaps making a bridge interface to the v6 router in the
NOC upstream.