1. netstat options
-a or --all: Display all sockets in the connection; -A<network type> or --<network type>: List the relevant addresses in the connection of this network type; -c or --continuous: continuously list network status; -C or --cache: Display the cache information of router configuration; -e or --extend: Display other network related information; -F or --fib: show FIB; -g or --groups : Display the list of members of the multicast function group; -h or --help : online help; -i or --interfaces: display the web interface information form; -l or --listening: Display the Socket of the server being monitored; -M or --masquerade: Display masquerade network connections; -n or --numeric: use the ip address directly without going through the domain name server; -N or --netlink or --symbolic: Display symbolic link names for network hardware peripherals; -o or --timers: show timers; -p or --programs: Display the program identifier and program name that are using Socket; -r or --route : Display Routing Table; -s or --statistice: Display network work information statistics table; -t or --tcp: Display the connection status of the TCP transport protocol; -u or --udp: Display the connection status of the UDP transport protocol; -v or --verbose: Display the instruction execution process; -V or --version: Display version information; - w or --raw: Display the connection status of the RAW transmission protocol; -x or --unix: The effect of this parameter is the same as specifying the "-A unix" parameter; --ip or --inet: The effect of this parameter is the same as specifying the "-A inet" parameter.
2. The usage of netstat can be found through netstat --help: as follows
3. List all ports (including listening and non-listening)
netstat -a #List all ports
netstat - at #List all tcp ports
netstat -au #List all udp ports
4. List all Sockets in listening state
netstat -l # only display listening ports netstat -lt #Only list all listening tcp ports netstat -lu #Only list all listening udp ports netstat -lx #Only list all listening UNIX ports
5. Display statistics for each protocol
netstat -s displays statistics for all ports
netstat -st displays statistics on TCP ports
netstat - su displays statistics for UDP ports
6. Display PID and process name in netstat output
netstat -pt
netstat -an
netsat -a --numeric-ports
netsat -a --numeric-hosts
netsat -a --numeric-users
7. Continuously output netstat information
netstat -c #Output network information every second
8. Display the Address Families that are not supported by the system
netstat --verbose
9. Display core routing information
netstat -r
Use the netstat -rn
display number format, without querying the hostname.
10. Find out the port the program is running on
View all information with root privileges
netstat -ap | grep ssh
Find out which process is running on the specified port:
netstat -an | grep ':80'
11. Display a list of network interfaces
netstat -i
source:
Detailed explanation of netstat command