Download and Add Cisco IOU and IOL To Eve-Ng

Complete guide on how to add Cisco IOU and IOL Images to Eve-ng. L2/L3 images of Switches and routers which helps you to practice for L3 devices with the same features and functions which original devices have. Cisco IOU/IOL images were released for Architecture and testing purposes but today Cisco IOU/IOL images are used for CCIE routing and switching practice for CCIE routing and switching.

Video Guide to add cisco iou/iol images to eve-ng.

1. Supported Images for Eveng

Eve-ng supports all the Cisco IOU/IOL images but below are recommended one.

TypeEVE Image NameVersionvRAM
L2L2-ADVENTERPRISEK9-M-15.1-20130726.binI86BI_LINUXL2-ADVENTERPRISEK9-M 15.1(20130726:213425)192

2. Download Cisco IOU and IOL Images

Images provided below are strictly for educational purposes and are not hosted on the server. We are just indexing the links found on the internet for educational purposes only.

You can download Cisco IOU/IOL images from the below links.

3. Add images to Eve-ng

IOL or IOS On Linux also called IOU or IOS On Unix. It is a simulator available for Cisco internal use only. IOL refers to the Linux version, compiled for i386 architecture. IOU refers to the Unix (Solaris) version compiled for Sparc architecture. The term IOU usually refers to IOL too.

Because IOL is an internal IOS version, IOL can be used by Cisco employees or by authorized customers only.

Upload the downloaded image to the EVE using for example FileZilla or WinSCP to:  /opt/unetlab/addons/iol/bin

Type the following command to fix permissions:/opt/unetlab/wrappers/unl_wrapper -a fixpermissions

4. Generate a License for IOU/IOL.

#! /usr/bin/python
print("Cisco IOU License Generator - Kal 2011, python port of 2006 C version")
print("Modified to work with python3 by c_d 2014")
import os
import socket
import hashlib
import struct

# get the host id and host name to calculate the hostkey
hostname = socket.gethostname()
for x in hostname:
 ioukey = ioukey + ord(x)
print("hostid=" + hostid +", hostname="+ hostname + ", ioukey=" + hex(ioukey)[2:])

# create the license using md5sum
iouPad1 = b'\x4B\x58\x21\x81\x56\x7B\x0D\xF3\x21\x43\x9B\x7E\xAC\x1D\xE6\x8A'
iouPad2 = b'\x80' + 39*b'\0'
md5input=iouPad1 + iouPad2 + struct.pack('!i', ioukey) + iouPad1

print("\nAdd the following text to ~/.iourc:")
print("[license]\n" + hostname + " = " + iouLicense + ";\n")
print("You can disable the phone home feature with something like:")
print(" echo '' >> /etc/hosts\n")
  • Copy the above text create a text file and save as with the name
  • After creating the license python script, upload it to the Eve-ng directory
  • After uploading the script go to the directory by using the below command-
    cd /opt/unetlab/addons/iol/bin/
  • Check the directory content by below command-
    ls -l
  • you will be able to see a file with the name –
  • Now run the python script by using the below command-
  • it will give you some like the below output
    root@eve-ng:/opt/unetlab/addons/iol/bin# python2
Cisco IOU License Generator - Kal 2011, python port of 2006 C version Modified to work with python3 by c_d 2014 hostid=007f0101, hostname=eve-ng, ioukey=7f0343Add the following text to ~/.iourc:


eve-ng = 972f30267ef51616;

Now, we will create licenses for IOU/IOL images

nano - c iourc

paste the license and press ctrl+x to save


eve-ng = 972f30267ef51616;

We have successfully licensed the Cisco IOU/IOL images.

5. Testing images in Eve-ng

cd /opt/unetlab/addons/iol/bin
touch NETMAP
LD_LIBRARY_PATH=/opt/unetlab/addons/iol/lib /opt/unetlab/addons/iol/bin/<iosname.bin> 1
IOS On Unix - Cisco Systems confidential, internal use only
Under no circumstances is this software to be provided to any
non Cisco staff or customers.  To do so is likely to result
in disciplinary action. Please refer to the IOU Usage policy at for more information.

              Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

           cisco Systems, Inc.
           170 West Tasman Drive
           San Jose, California 95134-1706

Adding Cisco IOU and IOL images to EVE-NG is a game-changer for network enthusiasts and professionals who are preparing for certifications such as the CCIE Routing and Switching. Originally designed for Cisco’s internal architecture and testing, these images have found their way into the hands of learners, providing an unparalleled simulation environment. By incorporating these L2 and L3 images of switches and routers, you can practice on virtual devices that offer the same features and functions as their physical counterparts.

This complete guide will walk you through the process of integrating Cisco’s powerful IOU/IOL images into your EVE-NG lab setup, ensuring you have the tools needed to simulate real-world networking scenarios and advance your skills.

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