Omron CJ1W-EIP21 Benutzerhandbuch

The TCP socket status can be confirmed using the socket status data returned for the FINS command
SOCKET STATUS READ (27 64).

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