Dummy Interface

Installing The Linux Dummy-Network Interface

If your NST system does not have an active NIC adapter installed or is off-line from the network, you can install a Dummy Network Interface Module to simulate a network computing environment. This can be quite useful for testing out various networking tools (e.g., Wireshark and Snort) with the Network Security Toolkit when off-line. Use the following procedure to install the Linux Dummy-Network Interface:

1. Add an IP address and host name to your "/etc/hosts" table. For example, an Internet address of 10.0.0.1 would result in:

     echo 10.0.0.1 $HOSTNAME >> /etc/hosts

2. Preload the dummy network driver on the machine. If this command is successful, you do not receive any messages from the server.

     # modprobe dummy

If you need to load more than one (1) dummy interface use the following (Three (3) in this example):

     # modprobe dummy numdummies=3

3. Bind the dummy established network interface to the $HOSTNAME configured IP address. Also shown are other bindings for virtual network interfaces using IP Address Aliasing

     # ifconfig dummy0 $HOSTNAME
     # ifconfig dummy0:0 10.0.0.2
     # ifconfig dummy0:1 10.0.0.3

4. Add a route other than “default” to the established connectivity to each virtual network interface.

     # route add $HOSTNAME dummy0
     # route add 10.0.0.2 dummy0:0
     # route add 10.0.0.3 dummy0:1

5. Check the network binding: This command gives below listed output:

     # ifconfig dummy0
       dummy0   Link encap:Ethernet  HWaddr 2A:7B:EA:49:69:E2
                inet addr:10.0.0.1  Bcast:10.255.255.255  Mask:255.0.0.0
                inet6 addr: fe80::287b:eaff:fe49:69e2/64 Scope:Link
                UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
                RX packets:0 errors:0 dropped:0 overruns:0 frame:0
                TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
                collisions:0 txqueuelen:0
                RX bytes:0 (0.0 b)  TX bytes:824 (824.0 b)
     #
     # ifconfig dummy0:0
       dummy0:0 Link encap:Ethernet  HWaddr 2A:7B:EA:49:69:E2
                inet addr:10.0.0.2  Bcast:10.255.255.255  Mask:255.0.0.0
                UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
     #
     # ifconfig dummy0:1
       dummy0:1 Link encap:Ethernet  HWaddr 2A:7B:EA:49:69:E2
                inet addr:10.0.0.3  Bcast:10.255.255.255  Mask:255.0.0.0
                UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1

6. Check the route binding: This command shows the routing as it is set up.

     # route -n
     Kernel IP routing table:
     Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
     10.0.0.1        0.0.0.0         255.255.255.255 UH    0      0        0 dummy0
     10.0.0.2        0.0.0.0         255.255.255.255 UH    0      0        0 dummy0
     10.0.0.3        0.0.0.0         255.255.255.255 UH    0      0        0 dummy0
     10.0.0.0        0.0.0.0         255.0.0.0       U     0      0        0 dummy0
     127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo

Removing The Linux Dummy-Network Interface

1. Unbind the dummy established network interface:

     # ifconfig dummy0 down;

2) Remove the dummy kernel module.

     # rmmod dummy;

References

Reference Info 1: Linux Network Administrators Guide