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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.example.com


DNS lookup

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

dig -t AAAA www.example.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 at the succession of the types of DNS requests starting from the root ?


0000  4ec9810000010000  000d000903636f6d  
0010  0000020001c00c00  0200010002a30000  
0020  1401630c67746c64  2d73657276657273  
0030  036e657400c00c00  0200010002a30000  
0040  040161c023c00c00  0200010002a30000  
0050  040164c023c00c00  0200010002a30000  
0060  040165c023c00c00  0200010002a30000  
0070  040169c023c00c00  0200010002a30000  
0080  04016bc023c00c00  0200010002a30000  
0090  040167c023c00c00  0200010002a30000  
00A0  040162c023c00c00  0200010002a30000  
00B0  04016ac023c00c00  0200010002a30000  
00C0  040166c023c00c00  0200010002a30000  
00D0  04016cc023c00c00  0200010002a30000  
00E0  04016dc023c00c00  0200010002a30000  
00F0  040168c023c0e100  1c00010002a30000  
0100  1020010501b1f900  0000000000000000  
0110  30c0d1001c000100  02a3000010200105  
0120  00d9370000000000  0000000030c08100  
0130  1c00010002a30000  10200105030d2d00  
0140  0000000000000000  30c0b1001c000100  
0150  02a3000010200105  0270940000000000  
0160  0000000030c07100  1c00010002a30000  
0170  102001050339c100  0000000000000000  
0180  30c0f1001c000100  02a3000010200105  
0190  0208cc0000000000  0000000030c09100  
01A0  1c00010002a30000  1020010503eea300  
01B0  0000000000000000  30c0c1001c000100  
01C0  02a3000010200105  03d4140000000000  
01D0  0000000030c06100  1c00010002a30000  
01E0  10200105021ca100  0000000000000000  
01F0  30                                  

0000  NÉ...........com
0010  .....À.......£..
0020  ..c.gtld-servers
0030  .net.À.......£..
0040  ..aÀ#À.......£..
0050  ..dÀ#À.......£..
0060  ..eÀ#À.......£..
0070  ..iÀ#À.......£..
0080  ..kÀ#À.......£..
0090  ..gÀ#À.......£..
00A0  ..bÀ#À.......£..
00B0  ..jÀ#À.......£..
00C0  ..fÀ#À.......£..
00D0  ..lÀ#À.......£..
00E0  ..mÀ#À.......£..
00F0  ..hÀ#Àá......£..
0100  . ...±ù.........
0110  0ÀÑ......£... ..
0120  .Ù7.........0À..
0130  .....£... ....-.
0140  ........0À±.....
0150  .£... ...p......
0160  ....0Àq......£..
0170  . ...9Á.........
0180  0Àñ......£... ..
0190  ..Ì.........0À..
01A0  .....£... ...î£.
01B0  ........0ÀÁ.....
01C0  .£... ...Ô......
01D0  ....0Àa......£..
01E0  . ....¡.........
01F0  0               
  • Domain Name System (response)
    • Transaction ID: 0x4ec9
      • Flags: 0x8100 Standard query response, No error
        • 1... .... .... .... = Response: Message is a response
          • .000 0... .... .... = Opcode: Standard query (0)
            • .... .0.. .... .... = Authoritative: Server is not an authority for domain
              • .... ..0. .... .... = Truncated: Message is not truncated
                • .... ...1 .... .... = Recursion desired: Do query recursively
                  • .... .... 0... .... = Recursion available: Server can't do recursive queries
                    • .... .... .0.. .... = Z: reserved (0)
                      • .... .... ..0. .... = Answer authenticated: Answer/authority portion was not authenticated by the server
                        • .... .... ...0 .... = Non-authenticated data: Unacceptable
                          • .... .... .... 0000 = Reply code: No error (0)
                          • Questions: 1
                            • Answer RRs: 0
                              • Authority RRs: 13
                                • Additional RRs: 9
                                  • Queries
                                    • com: type NS, class IN
                                      • Name: com
                                        • Name Length: 3
                                          • Label Count: 1
                                            • Type: NS (authoritative Name Server) (2)
                                              • Class: IN (0x0001)
                                            • Authoritative nameservers
                                              • com: type NS, class IN, ns c.gtld-servers.net
                                                • Name: com
                                                  • Type: NS (authoritative Name Server) (2)
                                                    • Class: IN (0x0001)
                                                      • Time to live: 172800
                                                        • Data length: 20
                                                          • Name Server: c.gtld-servers.net
                                                          • com: type NS, class IN, ns a.gtld-servers.net
                                                            • Name: com
                                                              • Type: NS (authoritative Name Server) (2)
                                                                • Class: IN (0x0001)
                                                                  • Time to live: 172800
                                                                    • Data length: 4
                                                                      • Name Server: a.gtld-servers.net
                                                                      • com: type NS, class IN, ns d.gtld-servers.net
                                                                        • Name: com
                                                                          • Type: NS (authoritative Name Server) (2)
                                                                            • Class: IN (0x0001)
                                                                              • Time to live: 172800
                                                                                • Data length: 4
                                                                                  • Name Server: d.gtld-servers.net
                                                                                  • com: type NS, class IN, ns e.gtld-servers.net
                                                                                    • Name: com
                                                                                      • Type: NS (authoritative Name Server) (2)
                                                                                        • Class: IN (0x0001)
                                                                                          • Time to live: 172800
                                                                                            • Data length: 4
                                                                                              • Name Server: e.gtld-servers.net
                                                                                              • com: type NS, class IN, ns i.gtld-servers.net
                                                                                                • Name: com
                                                                                                  • Type: NS (authoritative Name Server) (2)
                                                                                                    • Class: IN (0x0001)
                                                                                                      • Time to live: 172800
                                                                                                        • Data length: 4
                                                                                                          • Name Server: i.gtld-servers.net
                                                                                                          • com: type NS, class IN, ns k.gtld-servers.net
                                                                                                            • Name: com
                                                                                                              • Type: NS (authoritative Name Server) (2)
                                                                                                                • Class: IN (0x0001)
                                                                                                                  • Time to live: 172800
                                                                                                                    • Data length: 4
                                                                                                                      • Name Server: k.gtld-servers.net
                                                                                                                      • com: type NS, class IN, ns g.gtld-servers.net
                                                                                                                        • Name: com
                                                                                                                          • Type: NS (authoritative Name Server) (2)
                                                                                                                            • Class: IN (0x0001)
                                                                                                                              • Time to live: 172800
                                                                                                                                • Data length: 4
                                                                                                                                  • Name Server: g.gtld-servers.net
                                                                                                                                  • com: type NS, class IN, ns b.gtld-servers.net
                                                                                                                                    • Name: com
                                                                                                                                      • Type: NS (authoritative Name Server) (2)
                                                                                                                                        • Class: IN (0x0001)
                                                                                                                                          • Time to live: 172800
                                                                                                                                            • Data length: 4
                                                                                                                                              • Name Server: b.gtld-servers.net
                                                                                                                                              • com: type NS, class IN, ns j.gtld-servers.net
                                                                                                                                                • Name: com
                                                                                                                                                  • Type: NS (authoritative Name Server) (2)
                                                                                                                                                    • Class: IN (0x0001)
                                                                                                                                                      • Time to live: 172800
                                                                                                                                                        • Data length: 4
                                                                                                                                                          • Name Server: j.gtld-servers.net
                                                                                                                                                          • com: type NS, class IN, ns f.gtld-servers.net
                                                                                                                                                            • Name: com
                                                                                                                                                              • Type: NS (authoritative Name Server) (2)
                                                                                                                                                                • Class: IN (0x0001)
                                                                                                                                                                  • Time to live: 172800
                                                                                                                                                                    • Data length: 4
                                                                                                                                                                      • Name Server: f.gtld-servers.net
                                                                                                                                                                      • com: type NS, class IN, ns l.gtld-servers.net
                                                                                                                                                                        • Name: com
                                                                                                                                                                          • Type: NS (authoritative Name Server) (2)
                                                                                                                                                                            • Class: IN (0x0001)
                                                                                                                                                                              • Time to live: 172800
                                                                                                                                                                                • Data length: 4
                                                                                                                                                                                  • Name Server: l.gtld-servers.net
                                                                                                                                                                                  • com: type NS, class IN, ns m.gtld-servers.net
                                                                                                                                                                                    • Name: com
                                                                                                                                                                                      • Type: NS (authoritative Name Server) (2)
                                                                                                                                                                                        • Class: IN (0x0001)
                                                                                                                                                                                          • Time to live: 172800
                                                                                                                                                                                            • Data length: 4
                                                                                                                                                                                              • Name Server: m.gtld-servers.net
                                                                                                                                                                                              • com: type NS, class IN, ns h.gtld-servers.net
                                                                                                                                                                                                • Name: com
                                                                                                                                                                                                  • Type: NS (authoritative Name Server) (2)
                                                                                                                                                                                                    • Class: IN (0x0001)
                                                                                                                                                                                                      • Time to live: 172800
                                                                                                                                                                                                        • Data length: 4
                                                                                                                                                                                                          • Name Server: h.gtld-servers.net
                                                                                                                                                                                                        • Additional records
                                                                                                                                                                                                          • m.gtld-servers.net: type AAAA, class IN, addr 2001:501:b1f9::30
                                                                                                                                                                                                            • Name: m.gtld-servers.net
                                                                                                                                                                                                              • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                • Class: IN (0x0001)
                                                                                                                                                                                                                  • Time to live: 172800
                                                                                                                                                                                                                    • Data length: 16
                                                                                                                                                                                                                      • AAAA Address: 2001:501:b1f9::30
                                                                                                                                                                                                                      • l.gtld-servers.net: type AAAA, class IN, addr 2001:500:d937::30
                                                                                                                                                                                                                        • Name: l.gtld-servers.net
                                                                                                                                                                                                                          • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                            • Class: IN (0x0001)
                                                                                                                                                                                                                              • Time to live: 172800
                                                                                                                                                                                                                                • Data length: 16
                                                                                                                                                                                                                                  • AAAA Address: 2001:500:d937::30
                                                                                                                                                                                                                                  • k.gtld-servers.net: type AAAA, class IN, addr 2001:503:d2d::30
                                                                                                                                                                                                                                    • Name: k.gtld-servers.net
                                                                                                                                                                                                                                      • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                        • Class: IN (0x0001)
                                                                                                                                                                                                                                          • Time to live: 172800
                                                                                                                                                                                                                                            • Data length: 16
                                                                                                                                                                                                                                              • AAAA Address: 2001:503:d2d::30
                                                                                                                                                                                                                                              • j.gtld-servers.net: type AAAA, class IN, addr 2001:502:7094::30
                                                                                                                                                                                                                                                • Name: j.gtld-servers.net
                                                                                                                                                                                                                                                  • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                    • Class: IN (0x0001)
                                                                                                                                                                                                                                                      • Time to live: 172800
                                                                                                                                                                                                                                                        • Data length: 16
                                                                                                                                                                                                                                                          • AAAA Address: 2001:502:7094::30
                                                                                                                                                                                                                                                          • i.gtld-servers.net: type AAAA, class IN, addr 2001:503:39c1::30
                                                                                                                                                                                                                                                            • Name: i.gtld-servers.net
                                                                                                                                                                                                                                                              • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                                • Class: IN (0x0001)
                                                                                                                                                                                                                                                                  • Time to live: 172800
                                                                                                                                                                                                                                                                    • Data length: 16
                                                                                                                                                                                                                                                                      • AAAA Address: 2001:503:39c1::30
                                                                                                                                                                                                                                                                      • h.gtld-servers.net: type AAAA, class IN, addr 2001:502:8cc::30
                                                                                                                                                                                                                                                                        • Name: h.gtld-servers.net
                                                                                                                                                                                                                                                                          • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                                            • Class: IN (0x0001)
                                                                                                                                                                                                                                                                              • Time to live: 172800
                                                                                                                                                                                                                                                                                • Data length: 16
                                                                                                                                                                                                                                                                                  • AAAA Address: 2001:502:8cc::30
                                                                                                                                                                                                                                                                                  • g.gtld-servers.net: type AAAA, class IN, addr 2001:503:eea3::30
                                                                                                                                                                                                                                                                                    • Name: g.gtld-servers.net
                                                                                                                                                                                                                                                                                      • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                                                        • Class: IN (0x0001)
                                                                                                                                                                                                                                                                                          • Time to live: 172800
                                                                                                                                                                                                                                                                                            • Data length: 16
                                                                                                                                                                                                                                                                                              • AAAA Address: 2001:503:eea3::30
                                                                                                                                                                                                                                                                                              • f.gtld-servers.net: type AAAA, class IN, addr 2001:503:d414::30
                                                                                                                                                                                                                                                                                                • Name: f.gtld-servers.net
                                                                                                                                                                                                                                                                                                  • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                                                                    • Class: IN (0x0001)
                                                                                                                                                                                                                                                                                                      • Time to live: 172800
                                                                                                                                                                                                                                                                                                        • Data length: 16
                                                                                                                                                                                                                                                                                                          • AAAA Address: 2001:503:d414::30
                                                                                                                                                                                                                                                                                                          • e.gtld-servers.net: type AAAA, class IN, addr 2001:502:1ca1::30
                                                                                                                                                                                                                                                                                                            • Name: e.gtld-servers.net
                                                                                                                                                                                                                                                                                                              • Type: AAAA (IPv6 Address) (28)
                                                                                                                                                                                                                                                                                                                • Class: IN (0x0001)
                                                                                                                                                                                                                                                                                                                  • Time to live: 172800
                                                                                                                                                                                                                                                                                                                    • Data length: 16
                                                                                                                                                                                                                                                                                                                      • AAAA Address: 2001:502:1ca1::30