C:\WINDOWS\Desktop>netstat -a Active Connections Proto Local Address Foreign Address State TCP laptop:1027 LAPTOP:0 LISTENING TCP laptop:1030 LAPTOP:0 LISTENING TCP laptop:1035 LAPTOP:0 LISTENING TCP laptop:50000 LAPTOP:0 LISTENING TCP laptop:5000 LAPTOP:0 LISTENING TCP laptop:1035 msgr-ns41.msgr.hotmail.com:1863 ESTABLISHED TCP laptop:nbsession LAPTOP:0 LISTENING TCP laptop:1027 localhost:50000 ESTABLISHED TCP laptop:50000 localhost:1027 ESTABLISHED UDP laptop:1900 *:* UDP laptop:nbname *:* UDP laptop:nbdatagram *:* UDP laptop:1547 *:* UDP laptop:1038 *:* UDP laptop:1828 *:* UDP laptop:3366 *:*
As you can see, the output includes four columns, which show the protocol, the local address, the foreign address, and the state of the port. The TCP connections show the local and foreign destination addresses and the current state of the connection. UDP, however, is a little different; it does not list a state status because UDP is a connectionless protocol and does not establish connections. The following list briefly explains the information provided by the
netstat -a command:
Proto The protocol used by the connection.
Local Address The IP address of the local computer system and the port number it is using. If the entry in the local address field is an asterisk (
*), it indicates that the port has not yet been established.
Foreign Address The IP address of a remote computer system and the associated port. When a port has not been established, as with the UDP connections,
*:*appears in the column.
State The current state of the TCP connection. Possible states include established, listening, closed, and waiting.