Unix netstat COMMAND

netstat COMMAND:
nestat command displays statistics information and current state of network connections, protocol, ports/ sockets and devices.

SYNTAX:
The Syntax is
netstat [options]

OPTIONS:

-s	dispalys statics information about protocols.
-i	dispalys statistics information about the network interface.
-r	diplays routing table.
-c	displays statistics information and updates every second.
-l	displays information about all sockets that are in listening state.
-a	displays information about all sockets that are in listening and non-listening state.
-p	displays information about sockets with ProcessName and PID.

EXAMPLE:

1. To get statistics of network connections:
   

   netstat

   The sample output of above command:
   

   Active Internet connections (w/o servers)
   Proto	Recv-Q	Send-Q	Local Address	Foreign Address	State
   tcp	0	0	vhost:32803	LocalHost:smtp	TIME_WAIT
   tcp	0	0	vhost:32803	google.com:http	ESTABLISHED

   
   

   Where,
   Proto	-Specifies the Protocol used for connection.
   Recv-Q	-Specifies the Number of Bytes which are not recevied.
   Send-Q	-Specifies the Number of Bytes not send to destination.
   Local Address	-Specifies the local or source address and port.
   Foreign Address	-Specifies the destination address and port.
   State	-Specifies the current state of conection to the socket. ESTABLISHED - Connection is Established. TIME_WAIT - Waiting to receive packets. LISTEN - Listening to establish connection.

2. To Get Statistics of Protocols:
   

   netstat -s

   The Sample output of above command:

   IP: 5193 incoming packets delivered 4813 requests sent out

   Tcp: 4033 segments received 4813 segments send out

   Icmp: 41 ICMP messages received 178 ICMP messages sent

3. To Get statistics of Network Interface:
   

   netstat -i

   The sample output of above command:
   
   

   Kernel Interface table
   Iface	MTU	Met	RX-OK	RX-ERR	TX-OK	TX-ERR	Flg
   eth0	1500	0	1308	0	1345	0	BMRU

   This is the statistics information of Ethernet Card[eth0