netstat in UNIX / Linux / Solaris

Using the netstat command

This command is applicable to UNIX, Linux, Solaris, Ubuntu, Fedora OS's.

The netstat command displays the contents of various network-related data structures for active connections.

• netstat -in command
  This netstat function shows the state of all configured interfaces.

• netstat -i -Z command
  This function of the netstat command clears all the statistic counters for the netstat -i command to zero. Note : This will work if in your Linux box SE Linux is enabled.
• netstat -I interface interval
  This netstat function displays the statistics for the specified interface.

• netstat -a command
  The netstat -a command shows the state of all sockets.

• netstat -M command
  The netstat -M command displays the network memory's cluster pool statistics. Note : your should be supported with ip_masquerade.
• netstat -v command
  The netstat -v command displays the statistics for each Common Data Link Interface (CDLI)-based device driver that is in operation.

• netstat -p protocol
  The netstat -p protocol shows statistics about the value specified for the protocol variable (udp, tcp, ip, icmp), which is either a well-known name for a protocol or an alias for it.

• netstat -s
  The netstat -s command shows statistics for each protocol (while the netstat -p command shows the statistics for the specified protocol).

• netstat -s -Z
  This is an undocumented function of the netstat command. It clears all the statistic counters for the netstat -s command to zero. Note: to use this enable SE Linux.
• netstat -r
  Another option relevant to performance is the display of the discovered Path Maximum Transmission Unit (PMTU). Use the netstat -r command to display this value.