job screening question

Nick Olsen nick at
Thu Jul 5 17:28:40 UTC 2012

I have people waive the "I'm Cisco Certified" flag in my face all the time. 
Then proceed to ask me if we have a T1. To the point that it's no longer a 
valuable achievement in my eyes.

I'm certified to perform CPR in the state of Florida... I should go apply 
for a surgeon position at the local hospital.

Nick Olsen
Network Operations (855) FLSPEED  x106

 From: "James M Keller" <jmkeller at>
Sent: Thursday, July 05, 2012 1:19 PM
To: "Oliver Garraux" <oliver at>, nanog at
Subject: Re: job screening question

On 7/5/2012 1:11 PM, Oliver Garraux wrote:
> Seems fairly straightforward to me.  It'll break path MTU discovery.
> I would hope someone applying for an "IP expert" position would know 
> Could HR be mangling the question or something?
> Oliver
> -------------------------------------
> Oliver Garraux
> Check out my blog:
> Follow me on Twitter:
> On Thu, Jul 5, 2012 at 1:02 PM, William Herrin <bill at> wrote:
>> Hi folks,
>> I gave my HR folks a screening question to ask candidates for an IP
>> expert position. I've gotten some "unexpected" answers, so I want to
>> do a sanity check and make sure I'm not asking something unreasonable.
>> And by "unexpected" I don't mean naively incorrect answers, I mean
>> oh-my-God-how-did-you-get-that-cisco-certification answers.
>> The question was:
>> You implement a firewall on which you block all ICMP packets. What
>> part of the TCP protocol (not IP in general, TCP specifically)
>> malfunctions as a result?
>> My questions for you are:
>> 1. As an expert who follows NANOG, do you know the answer? Or is this
>> question too hard?
>> 2. Is the question too vague? Is there a clearer way to word it?
>> 3. Is there a better screening question I could pass to HR to ask and
>> check the candidate's response against the supplied answer?
>> Thanks,
>> Bill Herrin
>> --
>> William D. Herrin ................ herrin at  bill at
>> 3005 Crane Dr. ...................... Web: <>
>> Falls Church, VA 22042-3004

You would be surprised by some of the people I get off the street
applying for senior network engineering positions who couldn't connect
up a SOHO router and a dumb switch and make them work, let alone
understand how PMTU discovery works.

James M Keller

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