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How well do you know your configs?

By stretch | Friday, July 18, 2008 at 1:13 a.m. UTC

Try this: print out the entire running configuration from a device on your network, any device with which you're familiar. Sit down with the printed pages away from a computer, and attempt to annotate line by line the purpose of each configuration statement. Sounds easy, right? You might be surprised by how much of the config, although familiar, cannot be readily tied to a purpose. Keep a separate list of the lines you can't explain and research them.

I discovered how challenging this can be several years back when I set out to document a configuration template. Despite being familiar with the entire configuration, there were a number of lines which I simply had never bothered to investigate. It was a little embarrassing having to research these neglected yet significant configuration details which, for years, I had blindly copied and pasted without thought.

This exercise can serve a number of purposes:

  • Getting comfortable with a configuration template for a new device or network
  • Flagging extraneous or deprecated configuration items for removal
  • Testing the skill level of a new employee or candidate for hire

If implementing this exercise as an evaluation of junior staff, I suggest keeping the initial test results. Have him or her repeat the same exercise a month or two later, and compare the two outcomes to gauge progress.

Posted in Tips and Tricks


Aragoen Celtdra
July 18, 2008 at 4:56 p.m. UTC

When I started studying for my CCNA, I printed out all our routers' configs (which I am not all too familiar with) on an 11x17" page and have it posted on my wall at home. I've been slowly going through it trying to understand each line as I come across them in my studies. It helps bring perspectives to how certain things are configured and the different iterations of commands (from basic to advanced).
I can say that I've felt more and more confident about what I know now, based on how well I understand these configurations at this point in time compared to when I started studying them.

Joey Boyer
July 18, 2008 at 5:31 p.m. UTC

Great idea Jeremy. I can definitely see us trying that in the very near future.

Patrick Barber
August 7, 2008 at 1:36 p.m. UTC

That is hard...i am familiar with all my devices...but by trying this exercise...not that familiar

Curtis LaMasters
August 15, 2008 at 2:45 a.m. UTC

I have done this exercise over and over and still to this day find something that I do not know what does....You are right, this is embarrassing, but always serves as a good reminder, a gut check if you will. I started doing this when I was in the Marines. I used it as a tool for teaching my peers and was very successful. Great exercise and thank you for reminding me of it.

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