The Transmission Control Protocol header

Following our discussion on the IP header for the packet, we captured in Wireshark. Let's check out the TCP header:

We can see that the TCP header contains the following sections:

  • Source Port: The port that generates the packet.
  • Destination Port: The port at which the data is addressed for a particular host.
  • Sequence number: The first data byte position.
  • Acknowledge number: The next data byte the receiving host is expecting.
  • Header Length: The length of the Transport layer header in 32-bit words.
  • Flags: The control bit field has the following types of values:
    • URG: Prioritize data
    • ACK: Acknowledge ...

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