What is netstat command?
netstat (network statistics) is a command-line utility used to display various network-related information on a computer. It provides information about active network connections, listening ports, routing tables, interface statistics, masquerade connections, and more. The exact functionality and output of netstat can vary slightly depending on the operating system you’re using.
-a -all : Show both listening and non-listening sockets. With the –interfaces option, show interfaces that are not up
# netstat -a | more : To show both listening and non-listening sockets.
List all tcp ports.
# netstat -at : To list all tcp ports.
List all udp ports.
# netstat -au : To list all udp ports.
List only listening ports.
# netstat -l : To list only the listening ports.
List only listening TCP ports.
# netstat -lt : To list only the listening tcp ports.
List only listening UDP ports.
# netstat -lu : To list only the listening udp ports.
List only the listening UNIX ports
# netstat -lx : To list only the listening UNIX ports.
List the statistics for all ports.
# netstat -s : To list the statistics for all ports.
List the statistics for TCP (or) UDP ports.
# netstat -st(TCP) : To list the statistics for TCP ports.
netstat -su(UDP) : List the statistics for UDP ports.
Display PID and program names in the output.
# netstat -pt : To display the PID and program names.
Print the netstat information continuously.
netstat will print information continuously every few seconds.
# netstat -c : To print the netstat information continuously.
The non-supportive address families in the system.
# netstat --verbose : To get the non-supportive address families in the system.
At the end, we have something like this :
The kernel routing information.
# netstat -r : To get the kernel routing information.
The port on which a program is running.
# netstat -ap | grep ssh : To get the port on which a program is running.
Which process is using a particular port:
# netstat -an | grep ':80' : To get the process which is using the given port.
List of network interfaces.
# netstat -i : To get the list of network interfaces.
Display extended information on the interfaces (similar to ifconfig) using netstat -ie: # netstat -ie : To display extended information on the interfaces