Solution

The correct answer is Option 1) 52100

Explanation

• A UDP header is 8 bytes (16 hexadecimal characters) long.
• It consists of four fields, each of 2 bytes (4 hex characters):
  • Source Port
  • Destination Port
  • Length
  • Checksum
• Given UDP header: CB84000D001C001C
• The source port is represented by the first 4 hexadecimal characters: CB84
• Convert hexadecimal CB84 to decimal:
  • C = 12, B = 11
  • (12 × 16³) + (11 × 16²) + (8 × 16¹) + (4 × 16⁰)
  • = 49152 + 2816 + 128 + 4 = 52100

Hence, the source port number is 52100.