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

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DNS packets


Question 1: A closer look at DNS over TCP

Although DNS is mainly used over UDP, there are some situations where it can be used over TCP as well. The attached packet trace contains a TCP connection that was used by dig to interact with the Domain Name System.

Download the packet trace and select the affirmations below that are valid.

If you do not have any packet dissector on your machine, you can visualize the packet trace in the question below.

Question 2: The packet trace

0000  9b7100356120043e  00000000a0005f50  
0010  13030000                            

0000  .q.5a .>......_P
0010  ....            
  • Transmission Control Protocol, Src Port: 39793, Dst Port: 53, Seq: 0, Len: 0
    • Source Port: 39793
      • Destination Port: 53
        • TCP Segment Len: 0
          • Sequence number: 0 (relative sequence number)
            • Acknowledgment number: 0
              • 1010 .... = Header Length: 40 bytes (10)
                • Window size value: 24400
                  • Calculated window size: 24400
                    • Checksum: 0x1303 [unverified]
                      • Urgent pointer: 0