Use “netstat -an” command to check port state, in Windows 2000/XP system, we could use this command under command prompt to check  system port state, and it could list the port number and its state that system is opening. And there are some sentences under state, now I simply explain what these words are for:
LISTEN: listen to the connection request of TCP port from remote
SYN-SENT: after sending connection request again, please wait for the matched connection request.
SYN-RECEIVED: after receiving and sending a connection request again, please wait for the confirm from the other side for the connection request.
ESTABLISHED: represents an opened connection
FIN-WAIT-1: wait for remote TCP connecting interruption request, or the confirm for previous connecting interruption request.
FIN-WAIT-2: wait for connecting interruption request from remote TCP
CLOSE-WAIT: wait for connecting interruption request from local user
CLOSING: wait for the confirm for the connecting interruption from remote TCP.
LAST-ACT: wait for the confirm for the original connecting interruption request sending to remote TCP.
TIME-WAIT: wait for enough time to ensure the remote TCP has received the confirm for connecting interruption request.
CLOSED: no any connection state.