utilites: ss

ss — utility for monitoring sockets

ss -a // information about all sockets

ss -t -a // information about all tcp sockets

ss -u -a // information about all udp sockets

ss -t & ss -u // information about only established connections

ss -l // list listening sockets

ss -lp // list listening sockets with process name

ss -o state established ‘( sport = :22 )’ // who is now on port 22

ss -4 // statistics only for ipv4 protocol