Which IPv6 prefix format defines the destination of a dynamic 6to4 tunnel?

Question

Options

• A2001:db8::/32
• B2002::/16
• Cfe80::/10
• Dff00::/8

• A
  8% (4)
• B
  87% (45)
• C
  2% (1)
• D
  4% (2)

Explanation

The 6to4 tunneling mechanism (defined in RFC 3056) uses the 2002::/16 prefix to embed an IPv4 address into an IPv6 address, creating a 48-bit prefix of the form 2002:<IPv4-hex>::/48. The embedded IPv4 address serves as the tunnel endpoint, making the tunneling dynamic - no manual configuration of the remote end is required. When a 6to4 router receives a packet destined for a 2002::/16 address, it extracts the embedded IPv4 address (bits 17–48) and uses it as the destination of the IPv4 encapsulating packet, dynamically resolving the tunnel endpoint. Option A (2001:db8::/32) is the documentation/example prefix used in RFCs, not for tunneling. Option C (fe80::/10) is the link-local address range. Option D (ff00::/8) is the IPv6 multicast prefix. Only 2002::/16 is specifically allocated for 6to4 tunneling.

No community discussion yet for this question.