DA - all good except pinging DTE's

I am setting up the DACA for our new Win 2012 server. I got the Dynamic Tunneling Endpoints setting from the registry. I'm unable to ping those addresses from the da client.

Everything else I can try works great, like pinging internal resources, access network shares, gpupdate, sccm updates.

The dte addresses start with fd66:e1b1:9b15:1000, should they not start with 2002 ?

Config is Win 2012, single Nat IP addr. using iphttps connection.

Thanks, Jon