GNS3 emulated hardware and FAQs


Q. Will you support Cisco switching?

A. Switching is going be supported in GNS3 using L2IOU images, which are special IOS images made to work on PC/Linux. These are more like generic Cisco switches with most of the same features as in real switches. So in the end you can have 90% of the same features, just a bit slower.

Q. Will switching work on Windows or Mac OS X?

A. Currently, L2IOU images work only on Linux or Solaris. On Windows and Mac OS X, the current plan is to use a virtual machine to run L2IOU but we are still looking for an alternative technical solution.

Q. Why not supporting 100% of Cisco switching features?

A. Simply because L2IOU images do not support all of the features, we suspect that some of them require the dedicate hardware found in Cisco devices in order to work, other features are simply buggy in currently available L2IOU versions. The one that are likely not to work are L3 Etherchannel, ISL trunks, DHCP snooping, Private VLAN, SPAN/RSPAN/ERSPAN, Port-security, Voice VLANs, MLS QoS and QinQ.

Q. Will I be able to run IOS-XE?

A. Cisco has released an IOS-XE version that work in VMware and KVM. Actually, you can already use it with GNS3 (please see this newsfor more details) but we want to make it easier.

Q. Will I be able to run NX-OS (Nexus)?

A. Cisco has a version of NX-OS than can run inside VMware ESX/ESXi. So in theory there is a way to use it with GNS3, we do not have more info because our focus is on routing & switching and security.

Q. Will I be able to run IOS-XR?

A. Cisco is planning to release a virtual IOS-XR named XRv early next year. After this release, it should be possible to integrate IOS-XR in GNS3.

Q. Will you provide ways to train for Cisco Data Center and Voice certifications?

A. Our focus is currently on Routing & Switching followed by security but we plan to check what can be technically done for Data Center and Voice in the future.

Q. Will IOS 15.x be supported?

A. IOS 15.x is currently only supported by the Cisco 7200 router in GNS3 but thanks to the IOU (IOS on Unix) integration, more IOS 15.x versions will be supported and with less resources too.

Q. Will you add more Cisco devices like ISR or other platforms?

A. No, the issue is that these devices have specialized hardware impossible or extremely hard to emulate. New Cisco devices will come in the form of VMware/KVM/VirtualBox appliances (see IOS-XE, IOS-XR and NX-OS questions above) and IOU images.

Q. Will Arista’s EOS be supported?

A.One of our user managed to run Arista vEOS within GNS3! See this forum post for more details. So all we need to do is maybe streamline this a bit and here it is, Arista’s EOS platform in GNS3!

Q. Will GNS3 support HP Procurve switches and routers in the future?

A. HP is starting to have some simulation/emulation products out there that can potentially be integrated in GNS3. We also have to see if a partnership is possible with HP. So yes probably in the future but not for the first release of the new GNS3.

  • Why my c2600 IOS image doesn’t work with Dynamips/GNS3?
    • Images for 2600 routers must be uncompressed to work.
  • Why my serial connection works though the interfaces are both DCE?
    • GNS3/Dynamips doesn’t emulate the physical layer which is why the serial connections work even though they are both DCE.
  • Is IOS version 15.0 supported?
    • 7206VXR is the only emulated router that supports this IOS. Please also note Cisco stated that only IOS 15.n(n)M releases will be supported on Cisco 7200 series routers.

Cisco 1700 Series

1700s have one or more interfaces on the motherboard, 2 subslots for WICs (excepting on 1710s), an no NM slots.


  • 1 FastEthernet and 1 Ethernet fixed ports (CISCO1710-MB-1FE-1E).
  • WIC slots: 0
  • Note that interfaces do not use a slot designation (e.g. “f0”)

1720, 1721 and 1750

  • 1 FastEthernet fixed port (C1700-MB-1ETH).
  • WIC slots: 2 (maximum of 2 Ethernet ports or 4 serial ports).
  • Note that interfaces do not use a slot designation (e.g. “f0”)

1751 and 1760

  • 1 FastEthernet fixed port (C1700-MB-1ETH).
  • WIC slots: 2 (maximum of 2 Ethernet ports or 4 serial ports).

WIC cards

Cisco 2600 Series

2600s have one or more interfaces on the motherboard, 2 subslots for WICs and 1 Network Module (NM) slot.


  • 1 Ethernet fixed port (CISCO2600-MB-1E).
  • NM slots: 1 (maximum of 4 Ethernet ports or 16 FastEthernet ports).
  • WIC slots: 3 (maximum of 6 serial ports).


  • 2 Ethernet fixed ports (CISCO2600-MB-2E).
  • NM slots: 1 (maximum of 4 Ethernet ports or 16 FastEthernet ports).
  • WIC slots: 3 (maximum of 6 serial ports).

2610XM, 2620, 2620XM and 2650XM

  • 1 FastEthernet fixed port (CISCO2600-MB-1FE).
  • NM slots: 1 (maximum of 4 Ethernet ports or 16 FastEthernet ports).
  • WIC slots: 3 (maximum of 6 serial ports).

2611XM, 2621, 2621XM and 2651XM

  • 2 FastEthernet fixed ports (CISCO2600-MB-2FE).
  • NM slots: 1 (maximum of 4 Ethernet ports or 16 FastEthernet ports).
  • WIC slots: 3 (maximum of 6 serial ports).

Network Modules

  • NM-1E (1 Ethernet port)
  • NM-4E (4 Ethernet ports)
  • NM-1FE-TX (1 FastEthernet port)
  • NM-16ESW (switch module: 16 FastEthernet ports)
  • NM-NAM (Network Analysis Module, not working).
  • NM-IDS (IDS Network Module, not working).

WIC cards

Cisco 3600 Series

3600s have 2 to 6 Network Module (NM) slots.


  • NM slots: 2 (maximum of 8 Ethernet ports, 32 FastEthernet ports or 8 serial ports).


  • NM slots: 4 (maximum of 16 Ethernet ports, 32 FastEthernet ports or 16 serial ports).


  • 2 FastEthernet fixed ports (Leopard-2FE).
  • NM slots: 6 (maximum of 24 Ethernet ports, 32 FastEthernet ports or 24 serial ports).

Network Modules

  • NM-1E (1 Ethernet port)
  • NM-4E (4 Ethernet ports)
  • NM-1FE-TX (1 FastEthernet port)
  • NM-16ESW (switch module: 16 FastEthernet ports, maximum of 2 modules per router)
  • NM-4T (4 serial ports)

Cisco 3700 Series

3700s have 2 FastEthernet interfaces on the motherboard, 3 subslots for WICs and 1 to 4 Network Module (NM) slots.


  • 2 FastEthernet fixed ports (GT96100-FE)
  • NM slots: 1 (maximum of 16 FastEthernet ports or 4 serial ports).
  • WIC slots: 3 (maximum of 6 serial ports).
  • Note: the 2691 is essentially a 3700 with 1 NM slot.


  • 2 FastEthernet fixed ports (GT96100-FE)
  • NM slots: 2 (maximum of 32 FastEthernet ports or 8 serial ports).
  • WIC slots: 3 (maximum of 6 serial ports).


  • 2 FastEthernet fixed ports (GT96100-FE)
  • NM slots: 4 (maximum of 32 FastEthernet ports or 16 serial ports).
  • WIC slots: 3 (maximum of 6 serial ports).

Network Modules

  • NM-1FE-TX (1 FastEthernet port)
  • NM-16ESW (switch module: 16 FastEthernet ports, maximum of 2 modules per router)
  • NM-4T (4 serial ports)
  • NM-NAM (Network Analysis Module, not working).
  • NM-IDS (IDS Network Module, not working).

WIC cards

Cisco 7200 Series

7200s have a different architecture. Only the 7206 is supported, it has 6 Port Adapters (PA) slots.


  • PA slots: 6
  • Note: VXR chassis, NPE-400 and C7200-IO-FE are the default in GNS3.

Chassis types

  • STD
  • VXR

Network Processing Engines (NPEs)

  • NPE-100
  • NPE-150
  • NPE-175
  • NPE-200
  • NPE-225
  • NPE-300
  • NPE-400
  • NPE-G2 (requires the use of NPE-G2 c7200p IOS images)

Input/Output Controllers

Can be inserted into slot 0 only.

  • C7200-IO-FE (1 FastEthernet port)
  • C7200-IO-2FE (2 FastEthernet ports)
  • C7200-IO-GE-E (1 GigabitEthernet port, Ethernet port is not functional)

Port Adapters

Online Insertion and Removal (OIR) is supported, allowing you to replace PAs while the router is running.

Cisco Catalyst Switches

At this moment, it is not possible to emulate Catalyst switches with Dynamips/GNS3. This is due to the impossibility to emulate ASIC processors used in those type of devices. However you can use the EtherSwitch module with 2600s, 3600s and 3700s Series. Keep in mind that this module works differently (uses the vlan database etc.) and doesn’t support the following features:

  • Access Switch Device Manager (SDM) Template
  • ACL – Improved Merging Algorithm
  • ARP Optimization
  • BGP Increased Support of Numbered as-path Access Lists to 500
  • BGP Restart Neighbor Session After max-prefix Limit Reached
  • BGP Route-Map Continue Support for Outbound Policy
  • Clear Counters Per Port
  • DHCP Snooping
  • DHCP Snooping Counters
  • Diagnotics Options on bootup
  • ErrDisable Reactivation Per Port
  • ErrDisable timeout
  • EtherChannel – Flexible PAgP
  • Etherchannel Guard
  • Fallback Bridging
  • Flex Link Bi-directional Fast Convergence
  • Flex Link VLAN Load-Balancing
  • Flex Links Interface Preemption
  • GOLD – Generic Online Diagnostics
  • IEEE 802.1ab, Link Layer Discovery Protocol
  • IEEE 802.1s – Multiple Spanning Tree (MST) Standard Compliance
  • IEEE 802.1s VLAN Multiple Spanning Trees
  • IEEE 802.1t
  • IEEE 802.1W Spanning Tree Rapid Reconfiguration
  • IEEE 802.1x – Auth Fail Open
  • IEEE 802.1x – Auth Fail VLAN
  • IEEE 802.1x – VLAN Assignment
  • IEEE 802.1x – Wake on LAN Support
  • IEEE 802.1X Multi-Domain Authentication
  • IEEE 802.1x RADIUS Accounting
  • IEEE 802.1x with Port Security
  • IEEE 802.3ad Link Aggregation (LACP)
  • IEEE 802.3af Power over Ethernet
  • IGMP Fast Leave
  • IGMP Version 1
  • IGRP
  • IP Phone Detection Enhancements
  • IP Phone Enhancement – PHY Loop Detection
  • IPSG (IP Source Guard)
  • Jumbo Frames
  • L2PT – Layer 2 Protocol Tunneling
  • MAC Authentication Bypass
  • MLD Snooping
  • Multicast Etherchannel Load Balancing
  • NAC – L2 IEEE 802.1x
  • NAC – L2 IP
  • NAC – L2 IP with Auth Fail Open
  • Packet-Based Storm Control
  • Per Port Per VLAN Policing
  • Port Security
  • Port Security on Private VLAN Ports
  • Private VLANs
  • QoS Policy Propagation via Border Gateway Protocol (QPPB)
  • Rapid-Per-VLAN-Spanning Tree (Rapid-PVST)
  • Reduced MAC Address Usage
  • Remote SPAN (RSPAN)
  • Smart Port
  • Spanning Tree Protocol (STP) – Loop Guard
  • Spanning Tree Protocol (STP) – PortFast BPDU Filtering
  • Spanning Tree Protocol (STP) – Portfast Support for Trunks
  • Spanning Tree Protocol (STP) – Root Guard
  • Spanning Tree Protocol (STP) – Uplink Load Balancing
  • SRR (Shaped Round Robin)
  • Standby Supervisor Port Usage
  • STP Syslog Messages
  • Switching Database Manager (SDM)
  • Trunk Failover
  • Trusted boundary (extended trust for CDP devices)
  • Unicast Mac Filtering
  • UniDirectional Link Detection (UDLD)
  • VLAN Access Control List (VACL)
  • VLAN Aware Port Security
  • Weighted Tail Drop (WTD)

Cisco PIX firewalls

A special version of Qemu called PEMU is embedded into GNS3 for emulating the PIX 525 Security Appliance. PIX software up to version 7.2(4) is supported.

Cisco ASA firewalls

Qemu/GNS3 emulates ASA5520 (ASA 5520 Series Adaptive Security Appliance) hardware to run ASA software up to version 8.0(2).

Cisco IDS sensors

Qemu/GNS3 emulates an IDS 4235/4215 Sensor. The software IPS is known to run with release 6.0.

Juniper routers

JunOS, the Operating System for Juniper routers is based on FreeBSD, an UNIX Operating System that runs on PCs. At this date JunOS versions for Juniper M series are known to work in GNS3.


Thanks to Qemu and VirtualBox, GNS3 can run many operating systems like Linux or Windows as well as a lot of appliances. To save you time, we provide ready-to-use Qemu and VirtualBox images that integrate Linux Microcore (command line) and Linux Tinycore (small graphical interface). These images are designed to not use much memory, allowing you to run many virtual hosts. They include the following tools and features:

  • Console support
  • IPv6 support
  • iperf, tcpdump, iproute2 and iptables
  • SSH and telnet servers
  • D-ITG (Distributed Internet Traffic Generator)


Dynamips/GNS3 uses a fair amount of RAM and CPU in order to accomplish its emulation magic. Instructions can be found in the user documentation to reduce this but you may also consider the following advices:

  • Use c36xx, c37xx or c7200 IOS images. They are usually more stable with Dynamips.
  • Run Dynamips/GNS3 on Linux or Mac OS X if you can, performance is better and Dynamips is far more stable.
  • Try to not use the latest IOS images, for instance versions >= 12.4, depending of the IOS features you want, running 12.3 or 12.2 versions requires a lot less memory and CPU.

Of course, the number of routers you can run at the same time also strongly depend of your amount of RAM and CPU. On average users can run 10 to 15 routers with routing protocols configured without any problem. Some have even ran more than 100 routers on the same PC.


Getting started with GNS3 (Installation and configuration)

Up & Running With GNS3 1.X

How to Setup GNS3

Adding your own PC to GNS3 with MS Loopback

MicroNugget: GNS3 and Windows 8

MicroNugget: How to Tune GNS3 to Avoid a 100% CPU Utilization?

MicroNugget: Connecting Virtual Box Hosts to GNS3 Networks

MicroNugget: Virtual PC Simulators & GNS3

MicroNugget: Using Wireshark with GNS3

MicroNugget: Connecting GNS3 to the Internet

MicroNugget: The ASA in GNS3

How To Install GNS3 1.0 on Windows 8.1

GNS3 1.0 was released to the world on October 21st, 2014. I have been using previous versions of GNS3 for some time now to simulate networks and to practice for my Cisco certifications. For those of you who aren’t familiar with GNS3, it is an application that allows you to build networks for free. The caveat there is you need to supply the images for your equipment. GNS3 supports Cisco, Juniper, HP, Arista, Citrix, and Brocade (as specified on their site, You build out a virtual lab which means there is no need to purchase physical hardware.

Before getting started, you’ll need to sign up on GNS3‘s website. Once you have an account. You can download GNS3. Click on the Windows download button to begin.

Download GNS3 for Windows

Once you open the installation file, click through the standard setup screen and agreement until you get to the Choose Components section.

How to Install GNS3

GNS3 Components

Select all the components you will need – almost everything. SolarWinds is a new application packaged with GNS3. If you already have some of the components installed, such as Wireshark, you can uncheck it.

Location of Installation

After completing installation, Start GNS3.

Upon opening GNS3, you will be prompted to save your new project locally or in the cloud. For the purposes of setting up GNS3 I will skip this.

Store GNS3 project files locally or in the cloud

Click on Edit and then Preferences.

Editing preferences of GNS3

Expand Dynamips and select IOS routers.

Add new IOS images

This is where you must supply your IOS image. I cannot supply these images for you. Click on New to add your image.

Add new IOS image in GNS3

Enter the name of the Image and its platform.

Add a name and platform

Set the amount of RAM to be allocated to IOS.

Allocated ram

Select the default adapters you want installed for each new instance of this device.

The default adapters for the template

After you finish, the router will be displayed with its settings.

List of images

Click on the General tab to view your settings. Make any changes as you see fit.

GNS3 General Preferences

The Console applications tab is where you can configure what application is to be used to console into your devices within GNS3.

Putty for console

The Packet capture tab displays your settings for capturing traffic on links between your devices within GNS3. Notice the capture analyzer command using SolarWindows Response Time Viewer.

Wireshark for packet capture

Click OK to close the Preferences window.

The big window in the middle of GNS3 is your topology view. This is wear you drag and drop devices from the left menu item.

GNS3 Main Window

To add a device, click on one of the symbols on the left and drag and drop the IOS image you’ve uploaded to GNS3.

Click and drag

The Topology Summary window will display a list of all your devices. A red orb signifies a device that is off. A green orb means the device is on.

Right click on your device and click on Start to turn on your device. Right click again and select Console to bring up Putty to manage your device.

Device Menu

Happy labbing!

GNS3 1.2.1 installation on Ubuntu 14.04

As mentioned in an earlier post GNS3 is moving ahead fast. Currently at version 1.2.1 the GNS3 is looking great. Compared with the version 1.0 Beta 1 which I had installed, the 1.2.1 is not only more stable, but it has the Menu more clean and compact. For example now there is only one Preferences menu where you can adjust all your settings.

During the installation of 1.0 Beta 1 I made some notes in Evernote and it prove to be very useful as the installation was pretty messy. With 1.2.1 I did the same thing, but the installation was very smooth. Still, I said that if I made those notes maybe I should share them for those interested in a quick installation. A more complete guide can be found on GNS3 Community.

1. Download GNS3 1.2.1

Head over to, create and account and download the bundle archive for Linux.

If you for some reason you don’t want to create an account, you may download each package individually from

The following lines will assume that you have the bundle archive.

2. Install Ubuntu 14.04 dependencies

3. Unzip the bundle archive

You should see 5 packages in GNS3-1.2.1 folder:

4. Install Dynamips

To check if the correct version is install:

You should see in the output 0.2.14

5. Install GNS3 Server

To check if the GNS3 Server is installed correctly:

If you see some output other than an error, than you’re fine.

6. Install GNS3 GUI

To test if the installation is working:

You should see a graphical interface of GNS3 launched.

At this moment you have a working GNS3 environment if you want only want to test Cisco hardware emulators. I strongly recommend to continue and install also the rest of the components. Who knows when you’ll need them

7. Install IOUyap (Optional, if you will use IOU images)

To test the installation:

8. Install VPCS (Optional, if you want to use VirtualPC)

For the third line, the 64 represent 64bit, as my Ubuntu 14.04 is build on 64bit.
The values can be:
– 32 or i386 for 32bit OS
– 64 or amd64 for 64bit OS

Please be sure to use the correct one for your OS.

To test the VPCS:

You should see a Virtual PC being launched. Leave the console with letter q.

9. Install VirtualBox (Optional, if you want to launch VMs)

Download the correct version for your system from The following lines will assume an Ubuntu 14.04 64bit OS.

You can also use the instructions at and go for an APT installation.The choice is yours.

10. Install Qemu (Optional, if you want to use qemu images)

11. Install IOU (Optional, if you want to use IOU images)

I’m not a legal matter expert, and the usage of IOU is sort of grey area. Because of this, I’m not going to cover this chapter.

You’re ready to go. Start the GNS3 GUI:

Some things to check before going live:

  • check in the menu Edit > Preferences to set your desired Paths (in General sections) and to check the paths for the binaries (dynamips, vpcs, iou, virtualbox…)
  • add the IOS, virtualbox vm, iou images
  • in case of Cisco hardware emulators don’t forget to find the IdlePC value (when you add the IOS image or later with the start of your first router with a certain image) otherwise your CPUs will cry.

If something does not work as described or you need help please let me know in Comments.

[Update 1]

If you get the following error during installation of iouyap:

Try to install the iniparser as follows:


and finally iouyap

How to convert .img files to .vdi for Virtualbox

To convert an .img file to .vdi in Linux, so that you can directly use it in VirtualBox, open a terminal and paste this:

VBoxManage convertdd  file.img file.vdi

For instance, to convert the recently mentioned ChromeOS Cherry from .img to .vdi:

VBoxManage convertdd ChromeOS-Cherry.img ChromeOS-Cherry.vdi

To do this is Windows (I haven’t tested it but it should work), open cmd.exe (Start > Run, enter: cmd.exe), navigate to “C:\Program Files\innotek VirtualBox” (using the “cd” command), then run this (after placing the .img file inside the “C:\Program Files\innotek VirtualBox” folder):

VBoxManage.exe convertdd file.img file.vdi

Please let us know if you have tried this in Windows and rather or not it worked.

To use it in VirtualBox, create a new Virtual Machine, select “Use existing hard disk” and browse for the recetly converted .vdi file:

virtualbox use existing hard disk

How to do System Recovery on Lenovo z580

You will need to follow the steps below.

1. Backup all your data in C: drive.

2. Shut down the computer.

3. Remove any external media except the charger.

4. After removing, Press the small button with a ‘up to down’ near the power button.

5. The normal BIOS screen would occur and then the “windows is loading files” would show. Wait till it boots.

6. After booting, click the 2nd option which says “Onekey Recovery”

7. Then tick initial backup and click next. Two prompts would occur. Answer accordingly.

8. Now recovery would start

By now your machine should be back to the factory defaults.

Critical Error Failed to Create the VirtualBox COM object error and resolution

VirtualBox will not start and present a Critical Error dialog box which reads “Failed to create the VirtualBox COM object. The application will now terminate.” If you select Details for additional information, it may offer something similar to this error, if not the same, Callee RC: CO_E_SERVER_EXEC_FAILURE (0x80080005). Here is a solution that worked in this case and will get VirtualBox back up and running without losing any configuration changes.

I recognize this error will likely occur on multiple versions of this application, however, for the sake of disclosure, the error occured using Oracle VirtualBox 4.3.6 on a Microsoft Windows 7 Professional (64-bit). During the re-install, I elected to upgrade to the latest, at the time of this writing, Oracle VirtualBox 4.3.8.


The Process

  • Navigate to your profile and look for the .VirtualBox folder. For example, C:\Users\\.VirtualBox
  • Copy the VirtualBox.xml to somewhere safe, like your desktop
  • Uninstall VirtualBox
  • Delete the .VirtualBox folder
  • Re-install VirtualBox and the option package.
  • Start VirtualBox
  • Close VirtualBox
  • Navigate to your profile and look for the .VirtualBox folder. For example, C:\Users\\.VirtualBox
  • Rename the VirtualBox.xml to VirtualBox.xml.old
  • Copy your original VirtualBox.xml to the .VirtualBox folder
  • Start VirtualBox

Note: If you are presented with a hardware error message of some sort, here the corrections may be made. In my case, there was a referenced hard disk that was unavailable. So I deleted it using the configuration window that was presented.

Everything should be working as expected.