09-04-2020 11:30 AM
TCP RST flag may be sent by either of the end (client/server) because of fatal error. So if you take example of TCP RST flag, client trying to connect server on port which is unavailable at that moment on the server.
Now for successful connections without any issues from either of the end, you will see TCP-FIN flag.
Now in case, for a moment particular server went unavailable then RST will happen and user even don't know about this situation and initiated new request again And at that time may be that server became available and after that connection was successful. So In this case, if you compare sessions, you will find RST for first session and 2nd should be TCP-FIN. So like this, there are multiple situations where you will see such logs.
