Interviews often start with softball questions like…
So why are you interested in working for our company?
This question gives the candidate an easy way to warm-up and could give the interviewer some insights into the candidate. I’ve asked this question many time and sometimes heard a reply like..
I really want to learn about large scale networks. My current network is too small and is limiting my progress.
Good answer, right? At first glance this candidate gives a good impression. It seems we have hungry candidate who is eager to learn. Let’s dig a little deeper….
Can you give me an example of where you’ve dived deep into a technology which is already deployed in your network?
This follow up question is often met with silence.  As an interviewer the first response raises a yellow flag. Its great to find a candidate with ambition, but you need to show that that you’ve already started teaching yourself.
In my view, if you haven’t tried to understand your current network in great depth or breadth, however small it is, then you don’t deserve an opportunity to work at larger scale or to move to a more design focussed position.
The best way of progressing your network knowledge is to explore the network you currently have. Take firewalls and load-balancers for instance. You can use these devices to teach yourself about proxying, NAT, IPSec, HTTP and it’s headers, SMTP, DNS, TCP performance and offload, SSL, PKI, etc.
You can take a similar approach with routing and switching. What happens if link-x or router-y fails? Would you design it that way? What are the benefits of the current design, what are the trade-offs, what are the alternatives? Can you go through each line of config and explain what it does?
If you want to learn, learn. If that get’s you a bigger better job, I’ll be the first to congratulate you. However, if you can’t roll-up your sleeves and dig into your current network, then you are fooling yourself into thinking that a new job will fix your lack of curiosity. Richard Feynman said it best.
The first principle is that you must not fool yourself and you are the easiest person to fool.
 Don’t worry, I’m not trying to trip up the candidate. There are other ways to ask this question, such as ‘what is your favourite networking or systems technology’. The engineer may be spread thin in a small shop, but that may make them a more rounded engineer. If they were prepared to learn DNS/LDAP/AD/SMTP as a network engineer, that breadth is just as useful.
Image Credit: Tamiko Thiel via CC3.0