Announcing: New Config Labs, with Packet Tracer and CML Support

 In Config Lab, General, Hands-on, News

Some of you, particularly those that subscribe to the blog, will have noticed a lot of posts here at the blog in mid-October 2021. I thought I’d give you a quick update on what I’m doing here to preempt some of your questions. In short: I’ve replaced all the old Config Lab posts with replacement posts. The new posts have some new features and new labs as well. Read on if interested!

What are Config Labs?

Most of the content at the blog has to do with CCNA. To help you use the content, I organize most posts in two ways: By the type of post and by the Book/Part/Chapter the content matches. If you’re using my books, you can use the Book/Part/Chapter organization to find all posts related to where you are in the book. The post-type organization helps you review more broadly while focusing on one type of exercise, like QA or labs.

Config Labs make up one of the two current lab categories here at my blog. (The other, Packet Tracer Cert Guide Labs, help you re-create the examples in the Official CCNA Cert Guides.) I’ve been writing Config Labs and posting them for about 10 years now. We just finished adding some new labs, revising them, adding features, and reformatting the pages. In particular:

  • The old Config Lab pages asked you to configure just by typing your configuration in a text editor or writing on a piece of paper. That helped include everyone, particularly in the era when Cisco Packet Tracer (CPT) was not available to everyone and before Cisco Modeling Labs (CML) existed.
  • The revised Config Lab pages move that focus so you can perform the labs in Cisco Packet Tracer or CML. You can still do the labs in an editor or on paper, but each lab comes with both Packet Tracer files with which to do the lab, along with tips about issues you might see with that feature in Packet Tracer.
  • Because more CCNA candidates use CPT than CML, the revised labs prefer using CPT, in that the labs use interface identifiers possible in CPT. CML sometimes does not support those identical interface IDs, so the revised lab pages help CML users work through the differences.
  • Each older lab existed as two posts: A lab and a lab answer post. Each new Config Lab has a single post, with the answers and explanations hidden at first to avoid spoiling the answers. Now you can stay on that single page and have everything you need to do the lab exercise.

Those are the highlights. For more detail, check out the About page for the Config Labs.

All These Posts, All at Once

Blogs normally have a regular cadence, like maybe a post every week. The revision and expansion of the Config Lab posts really don’t work well for that. So, after not posting any new posts for a year, I’m posting about 75 or so Config Lab posts all at once. (I am giving them different post dates and times just for my own purposes, but they’ll all publish on or about Oct. 17th-18th.)

Why bother telling you? If you’re subscribed to the blog you’ll get a bunch of subscription emails from me. You can ignore the emails if you like, and just look at the blog, for these publication dates:

Mid August 2021 through October 2021


That’s all the news. Go check out the posts – just click on the top menus for Hands-On… Config Labs 200-301. You can even select by Book and Book Part. (Book parts contain 3-5 chapters each.) And let me know what you think!

Config Lab: Pat w/ a Pool 1
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Maroof Hossain

Much better like this, thank you for the updates!


When configuring a switch to learn its IP address with DHCP, how then do I know the specific address the switch has received in order to use SSH/Telnet?


the config labs &pkt tracer labs are all updated here but what about q&a ?
I m currently studying the official ccna vol1,but i see that here on the website the q&a dates are very should i follow the q&a section here on the website ?if yes then till which year?am i missing any post that mentioned about this update?

Wendell Odom

Hi Sana,
Yes, the Q&A content here is quite old. They questions are generally still useful, so I keep them on the site. However, you have the book, which has a great set of questions that come with the book. You should use those and consider the Q&A here as extras if you want more and if you find them useful.


I’m a little late in seeing this announcement, but I have taken a quick look at some of the added Packet Tracer content, pretty incredible. I am sure it is a great resource to current candidates 🙂


Wendell Odom

If you used my books for CCNA and didn’t see the links there, my apologies. They’re big resources with tons of features – striking a balance of pestering people repeating the “try this tool or that one” versus risking someone missing a useful tool is sometimes a challenge. If you’re not done with CCNA, hope you’ll find the labs useful!


I’m sorry, I did not mean for that to sound like a complaint on my part in any way. I did use your books for the ccna and made a lot of my own labs from your former ccent certskills and this one, so I have been aware of your blog here for quite some time and was able to find all the additional resources you make available in your books quite useful.

My comment was purely complimentary for all the work you have put into making the config labs, that have been around for quite some time in VIRL/CML, available in PT. I think it’s a great accomplishment worthy of note and will be very helpful to many. My ccna just happened to predate this, but you were no less of a help in my accomplishment.

Thank you

Wendell Odom

I hadn’t taken any offense, but I’m sure I just misunderstood you. Thanks for your kind follow-up.
All the best to you! Thanks again.


Hi Mr. Odom,
Referencing OCG Vol 2, page 161, Example 8-5.

On DAI, you wrote, “If you were to configure a switch only with commands shown in Example 8-5, the switch would filter all ARPs entering all untrusted ports in VLAN 11.”

The commands in Example 8-5 are as follows:
#ip arp inspection vlan 11
#interface GigabitEthernet1/0/2
#ip arp inspection trust

So, my question (my thought) is that without DHCP snooping and ARP ACLs, when only the commands (as stated above) are used, what would the switch compare the filtered ARPs against?


Wendell Odom

Hi Azza,
Thanks for the note.
I had to go back and read to get the context. And I see what’s probably confusing there.
So, what I mean is this:
Configure like Example 8-5 only, with no ARP ACL and no DHCP Snooping, and DAI filters all incoming ARPs on untrusted ports. The reason: There’s no table with which to find permissible entries, as you suggest in your question. So, DAI alone creates deny-all-ARP logic for untrusted ports.
Then, that sentence you quoted was meant to be a lead-in to suggest that you must also configure ARP ACLs or DHCP snooping, and here’s how to also config DHCP snooping in the scenario in the book, as per Example 8-6.

Hope this helps! Feel free to follow up.

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