A netstat command syntax
netstat -[rn]: Parameters related to routing.
Options and parameters:
-r: List the routing table, the function is the same as the route command.
-n: Do not use host name and service name, use IP and port number, like route -n.
netstat -[antulpc]: Parameters related to the network interface.
Options and parameters:
-a: list all connection status, including tcp/udp
/unix socket
-t: List connections with TCP packets only
-u: List connections with UDP packets only
-l: List only the network status of services that are already listening
-p: List PID and Program filename
-c: can be set to automatically update after a few seconds
Two netstat commands for various applications
1. List the current routing table status and display it with IP and port number.
2. List all the current network connection status, use IP and port number to display.
3. Display the currently activated network services.
4. Check the status of all network connections of the machine.
