So, say you have Client1 and Server1 and there is a TCP connection in the established state. The connection will remain in Half-Open until there is no transfer of data. One can be that one side crashed other will be that sudden power off machines. Half-Open ConnectionsĪ connection said to be half-open if one end of the TCP connection opens however the other end has closed it without the knowledge of others. Message seen at the server side will be “Connection closed by peer”. The server will dictate its process that connection close has been requested and will not send any segment to the client. When this happens, a RESET is sent to the server-side TCP from the client indicating the closing of the connection. Mostly CTL+c will send SIGINT or INTR interrupt calls to close the process in Linux. Now you interrupted the file in the middle of its opening with CTL+c or close the transfer in the middle. You send some commands to access some files on the remote server from the client and the client will display the content of the file. Let’s say you running programs like ssh or some other which used to access the application remotely from the local system. Mostly you will get an error on the application like telnet or ssh saying that “connection refused”. If the client initiates a connection to the server on the port which does exist, or the application is not running on the server then the server will send the RESET segment to the client. Below are the common reasons why TCP Reset would happen in a networking world.