There are some flags in TCP. I already understand what other flag names come from, such as SYN stands for synchronization. I also know that FIN is used to close a connection. What I don't understand is what exactly FIN means. Is it an abbreviation like other flags? I just can't make sense of it.
31 Answer
Why is the FIN flag in TCP called FIN?
FIN is an abbreviation for "Finish"
In the normal case, each side terminates its end of the connection by sending a special message with the FIN (finish) bit set. This message, sometimes called a FIN, serves as a connection termination request to the other device, while also possibly carrying data like a regular segment. The device receiving the FIN responds with an acknowledgment to the FIN to indicate that it was received. The connection as a whole is not considered terminated until both sides have finished the shut down procedure by sending a FIN and receiving an ACK.
Source TCP Connection Termination :
