On my VDS, both 6to4 and Teredo seem to work poorly (packet loss is about 40%). just-ping.com shows packet loss 10%-80% both for 6to4 and for Teredo address, but 0% for IPv4 address. When running ...
Obvious way (just setting up 6to4 tunnel and pinging) fails because ip command seems to be read-only on my VPS: can't change any networking-related settings. So I try using raw sockets: ...