What does a socket state TIME_WAIT, that can be seen in command like netstat, mean?
$ netstat -tulpan
<...>
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 172.31.11.100:58550 52.59.212.69:80 TIME_WAIT -
<...>
TCP guarantees the reliability by sending back Acknowledgment (ACK) packets back for a single or a range of packets received from the peer. This goes same for the control signals such as termination request/response. RFC 793 defines the TIME-WAIT state to be as follows:
TIME-WAIT - represents waiting for enough time to pass to be sure the remote TCP received the acknowledgment of its connection termination request.