Free Play Labs (Using Cert Guide Examples)

Free Play Labs

Cisco Press books separate CLI output from other text by placing it in a box. An Example shows CLI commands and command output, inside a box, with a numbered caption for easy reference, as shown in the following figure.

Along with the CCNA Official Cert Guides published in 2020, I created matching lab web pages here at the blog. Many students have repeatedly mentioned that they re-created the examples in the books using Cisco Packet Tracer, a network simulation tool. We helped by making that kind of activity more easily done. Why?

  • Why Packet Tracer, and not some other tool? The Packet Tracer (PT) software tool is free.
  • Why not just tell everyone to do all the work? Well, by starting with the files supplied in the blog series, we hope to get you to the important learning tasks much quicker.
  • Does it match the book pretty well? We use real gear to create all examples in the book, and Packet Tracer happens to mimic specific router and switch hardware models – so often times, we can make a .PKT file (as used by Packet Tracer) that uses the exact same interfaces used in the book’s examples.

A Brief History: Packet Tracer

First, to set the context for the tools, Cisco creates and offers Packet Tracer to anyone taking their Cisco Networking Academy courses. For instance, you can practice 90+% of the commands mentioned in my most recent CCNA 200-301 Official Cert Guides (Vol 1 and 2) with Packet Tracer. It’s a great tool.

For most of Packet Tracer’s 10+ years of existence, Cisco limited its use to Cisco Networking Academy students. To be an Academy student you had to take an Academy course over multiple school semesters. However, anyone in an Academy course could share the files for PT, or post them online for others to download, with no licensing mechanism to prevent the use of the software after download. As a result, it became common for people to obtain PT with a simple search and download.

Around 2016, Cisco took a new approach and began offering a free Academy course – “Introduction to Packet Tracer” – which allowed the user to download a legal and most recent version of PT directly from Cisco. Now anyone could sign-up for the course and download the latest version of PT.

How to Get Packet Tracer (Free)

Cisco offers Packet Tracer for free to anyone who signs up for a free Cisco Networking Academy Course about Packet Tracer itself. Easy Peasy! Just click the button to go to the page:

Try the Same - or Different - Show Commands

Let’s say that you see an example in the book and it lists output from show commands. You may want to repeat it in a lab, just to convince yourself. You may want to try different parameters on the command, or even try other related commands. But you don’t have a lab pod that can match the example, and it would take you some time to set it up to match the example even if you did have the gear.

Now all you need to do is open the supplied file with Packet Tracer (PT). We help you do that by providing a Packet Tracer (PT) file, with filetype .pkt, that you can use:

    • Interfaces match: We choose the same device models and interface IDs as supported by PT – and when we can’t, we list the differences in the per-chapter blog post
    • Configuration match: We configure each device with an initial configuration that matches the initial state of the example
    • Real Vs. PT Differences: We list differences between PT and real gear, along with any other known issues that might be a problem when re-creating the example

Configure Network Devices Just Like in the Books

Some book examples list configuration commands only. In those cases, the matching .pkt file (used by Packet Tracer) includes two versions of the same topology, each with a different configuration state:

Initial State: The devices include configuration that matches the configuration before the first line of the example.

Ending State: The devices include the same configuration in the initial state, plus all the configuration shown in the explicitly listed in the example.

The figure shows an image from within the Packet Tracer user interface for one .pkt file, with both versions of the topology shown.

You then have the option to use the top (initial state), bottom (ending state), or both parts of the .pkt file:

  • Interested in Config? Use the top to work through the example, adding the configuration yourself as listed in the example in the book.
  • Interested in Shows? Use the bottom if you are more interested in the show commands after adding the configuration shown in the example.
  • Interested in Before/After? Compare the output of different show commands before adding the configuration (at the top, in the initial state) and after the configuration has been added (at the bottom half of the user interface.)

Passwords and Other Conventions

Just to keep them all in one place, here are a few conventions:

Password is cisco: I think it’s useful to give all the devices a password given that password configuration is part of the CCNA exam. However, we made all passwords “cisco”.

We support a subset of Examples: When our team reviews a chapter to build .pkt files, we choose to support some but not all Examples. Mostly we choose to not bother if the example does not work well in PT due to differences in support commands, eg, the commands to configure the feature do not work in PT. In other cases it’s a more subjective choice. But we do not offer a file for all examples.

Interfaces documented if match or not: The interface description command either confirms that the interface IDs in PT match the book example, or it details the differences.

Hostname Suffixes with Two Topologies in One File: If the book example includes configuration, the .pkt file should show duplicate topologies: one with the initial configuration at the top of the example, and one with the ending configuration at the end of the example. The hostnames in .pkt should be pre-configured to use a suffix of -init for the devices in the top topology, and -end in the bottom (ending) topology.

Basic Administrative Configuration: We include some basic administrative configuration, unrelated to the specific examples. The following example details the configuration template used.

hostname R1
line con 0
 password cisco
 exec-timeout 0 0

line vty 0 15
 password cisco

enable secret cisco
no ip domain-lookup

! Beyond the router admin, use these commands:
vtp mode transparent
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