Essential SNMP, 2nd Edition

netstat

This program obtains network information from kernel data structures. The following command displays the routing table on Windows:

C:\>netstat -rn
 
Route Table
===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 03 47 b8 9d 10 ...... Intel(R) PRO/100 SP Mobile Combo Adapter - SecuR
emote Miniport
0x10004 ...00 09 5b e6 cd 6d ...... NETGEAR WG511 54 Mbps Wireless PC Card
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      192.168.1.3   192.168.1.120       25
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1       1
      192.168.1.0    255.255.255.0    192.168.1.120   192.168.1.120       25
    192.168.1.120  255.255.255.255        127.0.0.1       127.0.0.1       25
    192.168.1.255  255.255.255.255    192.168.1.120   192.168.1.120       25
        224.0.0.0        240.0.0.0    192.168.1.120   192.168.1.120       25
  255.255.255.255  255.255.255.255    192.168.1.120               2       1
  255.255.255.255  255.255.255.255    192.168.1.120   192.168.1.120       1
Default Gateway:       192.168.1.3
===========================================================================
Persistent Routes:
  None

And the same command on a Unix system:

$ netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
0.0.0.0         192.168.0.1     0.0.0.0         UG        0 0          0 eth0
$

Note the third column, ...