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;

3. Create the interface(s) (Example: Network Interface: dummy1):

ip link add dummy1 type dummy;

4. Bind an IPv4 Address to Network Interface dummy1:

ip addr add 10.0.0.1/24 dev dummy1;

--Or --

ip addr add ${HOSTNAME}/24 dev dummy1;

5. Bring the dummy1 Network Interface up:

ip link set dummy1 up;

6. If you need to load more than one (1) dummy interface use the following:

ip link add dummy2 type dummy;
ip link add dummy3 type dummy;
ip addr add 10.0.0.2/24 dev dummy2;
ip addr add 10.0.0.3/24 dev dummy3;
ip link set dummy2 up; 
ip link set dummy3 up;

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