All I want to achieve is to establish connection to my simple server (written in C# using TcpListener class, if it makes any difference), on my computer which is behind NAT. It has some IPv6 address (it's public IP, starting with 2001:0) on Teredo interface. However, I cannot even ping it from outside my network, for instance I'm trying to ping this address from this website http://mebsd.com/ipv6-ping-and-traceroute, result - 100% packet loss. As I understood from reading about Teredo, there is no need for some port forwarding? So where could be the problem?