Dummy Interface

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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 add 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;

7. Check the network bindings with the linux ip command:

[root@nst28-dev ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether 36:f5:1b:3a:12:41 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.1/24 scope global dummy1
       valid_lft forever preferred_lft forever
    inet6 fe80::34f5:1bff:fe3a:1241/64 scope link 
       valid_lft forever preferred_lft forever
3: dummy2: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether 6a:5c:3f:56:dc:2d brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.2/24 scope global dummy2
       valid_lft forever preferred_lft forever
    inet6 fe80::685c:3fff:fe56:dc2d/64 scope link 
       valid_lft forever preferred_lft forever
4: dummy3: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether 86:d5:9f:08:f1:32 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.3/24 scope global dummy3
       valid_lft forever preferred_lft forever
    inet6 fe80::84d5:9fff:fe08:f132/64 scope link 
       valid_lft forever preferred_lft forever

Removing The Linux Dummy-Network Interface

1. Unbind the dummy established Network Interface(s):

ifconfig dummy1 down;
ifconfig dummy2 down;
ifconfig dummy3 down;

2) Remove the dummy kernel module.

rmmod dummy;

References

Reference Info 1: Linux Network Administrators Guide

Reference Info 2: iproute2