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Author(s) Olivier Bonaventure
Deadline No deadline
Submission limit No limitation
Category tags dns

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DNS lookup for www.google.com


DNS lookup

A student collected a packet trace while running the following command:

dig -t AAAA www.google.com

This trace was collected with a resolver that does not store any record in its cache. Can you reorder the packets of this trace by looking and the succession of the types of DNS requests starting from the root ?


0000  d76d012000010000  0000000003636f6d  
0010  0000020001                          

0000  ×m. .........com
0010  .....           
  • Domain Name System (query)
    • Transaction ID: 0xd76d
      • Flags: 0x0120 Standard query
        • 0... .... .... .... = Response: Message is a query
          • .000 0... .... .... = Opcode: Standard query (0)
            • .... ..0. .... .... = Truncated: Message is not truncated
              • .... ...1 .... .... = Recursion desired: Do query recursively
                • .... .... .0.. .... = Z: reserved (0)
                  • .... .... ..1. .... = AD bit: Set
                    • .... .... ...0 .... = Non-authenticated data: Unacceptable
                    • Questions: 1
                      • Answer RRs: 0
                        • Authority RRs: 0
                          • Additional RRs: 0
                            • Queries
                              • com: type NS, class IN
                                • Name: com
                                  • Name Length: 3
                                    • Label Count: 1
                                      • Type: NS (authoritative Name Server) (2)
                                        • Class: IN (0x0001)