TCP

• for reliable, connection oriented data transmission where data integrity and order are essential, for example HTTP, FTP, SMTP etc.
• does a Three Way handshake to establish a connection between clients or a client and a server
• see [skibidi](https://walid-mahmoud.medium.com/osi-model-layer-4-tcp-3-way-handshake-108e60b8d2c8#:~:text=The%20Transmission%20Control%20Protocol%20(TCP,a%20client%20and%20a%20server.) for more in depth documentation

TCP flags:

• SYN : initiates a connection and synchronises sequence numbers
• ACK : confirms receipt of packets
• FIN : terminates a connection
• RST : tells the client that the port is closed
  • setting up IPtables in linux to respond with RST TCP packets
• gonna dig into these flags later:
  • PSH
  • URG
  • ECN-Echo
  • Nonce
  • CWR