What is a Teredo Bubble Packet used for?

What is a Teredo Bubble Packet used for?

• A. A NAT discovery probe
• B. A data-carrying IPv6 packet
• C. A Teredo keep-alive packet
• D. A routing update

Answer: (C)

Keeping Teredo alive across NATs relies on periodic keep-alive messages. The Teredo bubble packet is a small, non–data-carrying IPv6 packet sent over the Teredo tunnel specifically to refresh NAT bindings and firewall state. Even when there’s no user data to send, these bubbles prevent the NAT mapping from timing out, ensuring the Teredo tunnel remains usable for IPv6 reachability. It isn’t used to carry user data, isn’t a NAT discovery probe, and isn’t a routing update, so its sole purpose is to maintain the connection through periodic keep-alives.

Keeping Teredo alive across NATs relies on periodic keep-alive messages. The Teredo bubble packet is a small, non–data-carrying IPv6 packet sent over the Teredo tunnel specifically to refresh NAT bindings and firewall state. Even when there’s no user data to send, these bubbles prevent the NAT mapping from timing out, ensuring the Teredo tunnel remains usable for IPv6 reachability. It isn’t used to carry user data, isn’t a NAT discovery probe, and isn’t a routing update, so its sole purpose is to maintain the connection through periodic keep-alives.