Netstat :Netstat prints information about the Linux networking subsystem like network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.

command : netstat

examples :

$netstat

it display all the connections, routing tables, stats and open sockets

$netstat -nap

it displays all connected processes

here ‘-n’ gives numerical addresses instead of trying to determine symbolic host, port or user names.

‘-a’ gives all listening and non-listening sockets

‘-p’ gives the PID and name of the program to which each socket belongs

$netstat -s

it displays network statistics

here ‘-s’ gives summary statistics for each protocol

$netstat -a -i eth0

it results Kernel interface table info

‘-i’ gives table of all network interfaces

$netstat -atp

‘-t’ gives tcp connection stats

$netstat -aup

‘-u’ gives udp connection stats