How To Clone And Simulate Network Devices On Linux

How To Clone And Simulate Network Devices On Linux

This guide shows how to clone and simulate devices using free and
commonly used tools. This could be helpful while conducting network
stress-tests, network audits, etc.

This guide is divided into 4 simple steps:if(typeof __ez_fad_position != ‘undefined’){__ez_fad_position(‘div-gpt-ad-howtoforge_com-medrectangle-3-0’)};

  1. Installation of SNMP simulator
  2. Extracting SNMP record files from a physical device
  3. Adding a device to the list of simulated devices
  4. Starting the simulation

Requirements and tools:

  • 32 or 64 bit Linux distributions including: SuSE, RedHat
    Enterprise and Debian using i386 and x64 architectures.

  • TCP/IP network connection.
  • Java 1.6 or higher installed.
  • NET-SNMP tools
  • Verax SNMP Agent Simulator
  • Network monitoring software.


STEP 1: Installing SNMP agent simulator

First, you have to install the SNMP agent simulator (in this example
free Verax SNMP Agent Simulator).

  1. Download and unzip the simulator package (
  2. Recommended installation directory for the
    simulator: /usr/local/vxsnmpsimulator

  3. Create and move the simulator.conf
    file to the following directory: /etc/verax.d/

  4. Open the simulator.conf
    file, find the line with the SIMULATOR_HOME
    variable and change it to point to the installation directory.

  5. In
    the same simulator.conf file,
    find the line with the JRE_HOME
    file and and point to the folder where your java is located.

  6. Pay attention to the name of the interface (e.g. ‘eth1’) which is
    used to create interface aliases (e.g. ‘eth1:0’, ‘eth1:1’, etc.). The
    primary interface must be present before the SNMP simulator starts.

  7. Copy the simulatord
    file to /etc/init.d directory.

  8. Give execute permission to the following files:
    • chmod +x /etc/init.d/simulatord
    • chmod +x /usr/local/vxsnmpsimulator/conf/stop
    • chmod +x /usr/local/vxsnmpsimulator/conf/vlan_up
    • chmod +x /usr/local/vxsnmpsimulator/conf/vlan_down


STEP 2: Extracting SNMP record files from a physical device

  1. Extracting
    SNMP record files from a physical device can be done using the snmpwalk
    command. In order to do that, you have to install some tools allowing
    for snmpwalk
    command e.g. NET-SNMP.

  2. NET-SNMP can be installed by issuing the following command:

    yum install

  3. In order to prepare SNMP record file reflecting actual SNMP
    available at given IP address, use SNMP tools and issue the following

    snmpwalk -On -Oe -OU -v2c -c
    public address > [destination folder]/filename.txt


    snmpwalk -On -Oe -OU -v2c -c public > /root/cisco-snmprecordfile.txt

In this example is an IP
of a physical cisco switch we want to simulate.

the generated cisco-snmprecordfile.txt file contains OID values of the real
device and will be stored in the simulator/device directory.


Adding device to the list of simulated devices in SNMP simulator

to the vxsnmpsimulator/conf
directory, open devices.conf,
and add
a new <device> record for a simulated device.if(typeof __ez_fad_position != ‘undefined’){__ez_fad_position(‘div-gpt-ad-howtoforge_com-medrectangle-4-0’)};

In order to add a new device, you have to provide a path to a recently
generated file (cisco-snmprecordfile.txt) and add a new IP address.
Remember that the new IP address must be virtual.


<type filepath="../device/cisco-snmprecordfile.txt">
               <device ip="" netmask="24" port="161"</device>


STEP 4: Starting the simulation

Before running the Verax SNMP Simulator, make sure that port 161 is
available. If not, stop any process using port 161. 

  1. In order to start the SNMP Simulator, issue the following
    command in a terminal window

    simulatord start

  2. In order to open the Management Console, issue the
    following command in the terminal window (shell):

    simulatord console

  3. The
    Management Console will ask for connection details (it may connect to
    multiple simulators). By default, the simulator service process is
    running on the same server as the Management Console – in such a case
    confirm the default parameters by pressing “y” at the prompt:

    you want to connect to default simulator server? [y/n]

    Note: The default
    connection parameters
    are (localhost as the host name and 43500 for TCP

  4. Use the SHOW
    command to list simulated devices.

Well done, now we’ve got our cisco switch simulated by the SNMP
simulator at given IP address (


Final: Adding simulated device to the monitoring system

Make sure that SNMP simulator is started and simulating (type SHOW to
check a list of simulated devices).

start your network monitoring tool and add a simulated device just like
any other but remember to provide your simulated device IP.

Well done! You can now clone and simulate multiple SNMP devices or even

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