Omron SYSMAC CJ1W-EIP21 - Manual (Page 405)

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Appendix C
TCP Status Transitions
The TCP socket status can be confirmed using the socket status data returned for the FINS command
SOCKET STATUS READ (27 64).
Status Meaning
CLOSED Connection closed.
LISTEN Waiting for connection.
SYN SENT SYN sent in active status.
SYN RECEIVED SYN received and sent.
ESTABLISHED Already established.
CLOSE WAIT FIN received and waiting for completion.
FIN WAIT 1 Completed and FIN sent.
CLOSING Completed and exchanged FIN. Awaiting ACK.
LAST ACK FIN sent and completed. Awaiting ACK.
FIN WAIT 2 Completed and ACK received. Awaiting FIN.
TIME WAIT After closing, pauses twice the maximum segment life (2MSL).
rcv FIN
snd ACK
CLOSE
rcv ACK of FIN
rcv ACK of SYN
CLOSED
LISTEN
SYN
RECEIVED SYN
SENT
ESTABLISHED
CLOSING
CLOSED
WAIT
CLOSED
snd SYN, ACK
Passive OPEN
CLOSE
ACTIVE OPEN
snd SYN
snd SYN
SEND
CLOSE
rcv SYN
snd ACK
rcv SYN, ACK
snd ACK
snd FIN
CLOSE
snd ACK
rcv FIN
rcv ACK of FIN
snd FIN
rcv FIN
rcv ACK of FIN
Timeout=2MSL
LAST-ACK
CLOSE
snd FIN
TIME WAIT
FIN
WAIT-1
FIN WAIT-2
rcv SYN
snd ACK