netstat : see network connections or others
[SYNOPSIS] netstat OPTION
OPTION
-a display all sockets (default: connected)
-r display routing table
-i display interface table
-l display listening server sockets
-n don't resolve names
-p display PID/Program name for sockets
-v be verbose
-e display other/more information
-g display multicast group memberships
-s display networking statistics (like SNMP)
-o display timers
-c continuous listing
-M display masqueraded connections
-F display Forwarding Information Base (default)
-C display routing cache instead of FIB
-Z display SELinux security context for sockets