The process of TCP connection is established, if the client to the server sends a SYN packet, the server want to refuse the connection request, the server how to reply, only speak to look a lot of information on the three-way handshake connection is established, had not told how to refused to establish a connection,

CodePudding user response:

Server does not reply with respect to ok, connection is not established

CodePudding user response:

Usually a server without opening the port, the server protocol stack returns an RST packet to the SYN, of course also some system don't return packages, let the client to wait timeout,