How to Run Any Cisco Router's IOS From CMD - Forget Simulators

Today's tutorial is to teach you how to easily run any Cisco Router's IOS from your popular command prompt.

Why This Approach?

One of the reasons to do this is to be able to practice your routing configurations without the fuss of getting Packet Tracer or even firing up GNS3.

This methodology am about to reveal to you even saves you CPU usage as it is so light and requires only one line of code.

Step 1: Fire Up Notepad

As usual, just like my other tutorials my favourite text editing tool is the classic notepad.

Click Windows Key + R or Click Start and type notepad or Click All Programs>Accessories>Notepad

Step 2: Important Prerequisites

Install GNS3

Any version would do just fine.

Click here to download and install GNS3 (using GNS3-0.8.7-all-in-one for this presentation)

Essential Directory Paths to iOS: Locate where you have saved your Cisco iOS image files.

Step 3: Piecing It All Together

Open GNS3, click Edit>ISO images and Hypervisors

Select Image of preference for example in my case I chose a 2621 model.

Copy the following pieces which would be used in that one line code to fire up our Cisco Router.

Image file : C:\Users\Your-Username\GNS3\Images\c2600-adventerprisek9-mz.124-25d.image

Model: 2621

IDLEPC: 0x802484e4 (Click Auto calculation if you do not have already applied)

Default Ram: 144 MiB (You can increase the ram size to whatever you like)

Step 4: Where Everything Fits

For demonstration purposes here is mine:

Program Path: "C:\Program Files\GNS3\dynamips.exe"
Product Version: -P 2691
Ram: -r 144
IDLEPC Value: --idle-pc 0x802484e4
iOS Image Path: "C:\Users\Your-Username\GNS3\Images\c2691-adventerprisek9-mz.124-25d.image"

Copy and Paste this Line as shown in the screenshot above:

"C:\Program Files\GNS3\dynamips.exe" -P 2691 -r 128 --idle-pc 0x60a48e60 "C:\Users\<strong>Your-Username</strong>\GNS3\Images\c2691-adventerprisek9-mz.124-25d.image"