When the allowed parameter is true, the IPProtectionLevel option on the associated socket is set to Unrestricted. This may allow NAT traversal for a UdpClient depending on firewall rules in place on the system.
A Teredo address is an IPv6 address with the prefix of 2001::/32. Teredo addresses can be returned through normal DNS name resolution or enumerated as an IPv6 address assigned to a local interface.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)