AICCU (Automatic IPv6 Connectivity Client Utility) makes it easy for users to get IPv6 connectivity via SixXs. After having requested an account, tunnel and optionally a subnet, AICCU can be used to automatically configure the tunnel. AICCU supports TIC (Tunnel Information & Control protocol), which it uses for retrieving the tunnel configuration information, AYIYA, which allows tunnels to be created even behind firewalls and NATs.