Practice question

What is the purpose of a Teredo Bubble Packet?

  1. Initial tunnel negotiation
  2. Data transfer initiation
  3. Error reporting
  4. Keep-alive signaling

Answer: D — Keep-alive signaling

Keep-alive signaling. In Teredo, NAT devices and firewalls can drop mappings if there’s no traffic for a while. A Teredo Bubble Packet is a tiny UDP packet sent periodically to refresh the NAT translation and verify the path to the Teredo relay, ensuring the IPv6 tunnel stays usable even when no actual data is being transferred. It’s not about starting a tunnel, carrying data, or reporting errors—its role is to keep the tunnel alive.

Practice more: GCIA Fundamentals of Traffic Analysis Practice Test →