netstat

netstat

Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.
usage: netstat [-vWeenNcCF] [<Af>] -r         netstat {-V|--version|-h|--help}
       netstat [-vWnNcaeol] [<Socket> ...]
       netstat { [-vWeenNac] -i | [-cWnNe] -M | -s }

        -r, --route              display routing table
        -i, --interfaces         display interface table
        -g, --groups             display multicast group memberships
        -s, --statistics         display networking statistics (like SNMP)
        -M, --masquerade         display masqueraded connections

        -v, --verbose            be verbose
        -W, --wide               don't truncate IP addresses
        -n, --numeric            don't resolve names
        --numeric-hosts          don't resolve host names
        --numeric-ports          don't resolve port names
        --numeric-users          don't resolve user names
        -N, --symbolic           resolve hardware names
        -e, --extend             display other/more information
        -p, --programs           display PID/Program name for sockets
        -c, --continuous         continuous listing

        -l, --listening          display listening server sockets
        -a, --all, --listening   display all sockets (default: connected)
        -o, --timers             display timers
        -F, --fib                display Forwarding Information Base (default)
        -C, --cache              display routing cache instead of FIB

  <Socket>={-t|--tcp} {-u|--udp} {-w|--raw} {-x|--unix} --ax25 --ipx --netrom
  <AF>=Use '-6|-4' or '-A <af>' or '--<af>'; default: inet
  List of possible address families (which support routing):
    inet (DARPA Internet) inet6 (IPv6) ax25 (AMPR AX.25) 
    netrom (AMPR NET/ROM) ipx (Novell IPX) ddp (Appletalk DDP) 
    x25 (CCITT X.25)

Examples

List Sockets and connections

netstat -A inet -p

netstat -A inet -p | grep '^tcp' | grep '/' | sed 's_.*/__' | sort | uniq

Check for ports open for local only connections

netstat -tupan

Kernel interface table

netstat -i

List Sockets listening TCP Ports

netstat -lt

Active Internet connections (TCP ports)

netstat -ta

Statistics for each protocol

netstat -s

PID and process port

netstat -pt