A tunnel broker is a service which provides a network tunnel (similar to a VPN). These tunnels can provide encapsulated connectivity over existing infrastructure to a new infrastructure. Most tunnel broker provide free access to the new IPv6 Internet protocol. They use different systems like 6in4, 6to4, 6over4 or Toredo.
Using such a tunnel may be used to bypass Internet censorship. Since it is a new technology more research on this has to be done.
Free IPv6 tunnel brokers
- Hurricane Electric (http://www.tunnelbroker.net/)
- Sixxs (http://www.sixxs.net/)
- Go6/Freenet6 (http://www.go6.net/)