DNS and the UDP port numbers

Paste this command into your terminal:

The password to connect is

The UDP port numbers

DNS messages are carried inside UDP segments. Could you predict the source and destination port numbers of the DNS response knowing the DNS request ?

#	Length	Summary	Status
0	41 bytes	`Domain Name System (query)`
1	69 bytes	`Domain Name System (response)`

0000  f696003500294709  16eb012000010000
0010  0000000003777777  076578616d706c65
0020  036f726700001c00  01

0000  ö..5.)G..ë. ....
0010  .....www.example
0020  .org.....

User Datagram Protocol
- Source Port: 63126
- Destination Port: 53
- Length: 41
- Checksum: 0x4709 [unverified]
Domain Name System (query)
- Transaction ID: 0x16eb
- 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
  - www.example.org: type AAAA, class IN
    - Name: www.example.org
    - Name Length: 15
    - Label Count: 3
    - Type: AAAA (IPv6 Address) (28)
    - Class: IN (0x0001)

0000  ????????0045a528  16eb81a000010001
0010  0000000003777777  076578616d706c65
0020  036f726700001c00  01c00c001c000100
0030  0147d10010260628  0002200001024818
0040  9325c81946

0000  ????.E¥(.ë......
0010  .....www.example
0020  .org.....À......
0030  .GÑ..&.(.. ...H.
0040  .%È.F

User Datagram Protocol
- Source Port: ?
- Destination Port: ?
- Length: 69
- Checksum: 0xa528 [unverified]
Domain Name System (response)
- Transaction ID: 0x16eb
- Flags: 0x81a0 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
  - .... .... 1... .... = Recursion available: Server can do recursive queries
  - .... .... .0.. .... = Z: reserved (0)
  - .... .... ..1. .... = Answer authenticated: Answer/authority portion was authenticated by the server
  - .... .... ...0 .... = Non-authenticated data: Unacceptable
  - .... .... .... 0000 = Reply code: No error (0)
- Questions: 1
- Answer RRs: 1
- Authority RRs: 0
- Additional RRs: 0
- Queries
  - www.example.org: type AAAA, class IN
    - Name: www.example.org
    - Name Length: 15
    - Label Count: 3
    - Type: AAAA (IPv6 Address) (28)
    - Class: IN (0x0001)
- Answers
  - www.example.org: type AAAA, class IN, addr 2606:2800:220:1:248:1893:25c8:1946
    - Name: www.example.org
    - Type: AAAA (IPv6 Address) (28)
    - Class: IN (0x0001)
    - Time to live: 83921
    - Data length: 16
    - AAAA Address: 2606:2800:220:1:248:1893:25c8:1946

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

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