Seems fairly straightforward to me. It'll break path MTU discovery.

I would hope someone applying for an "IP expert" position would know

+1 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@houseofzen.org> Sent: Thursday, July 05, 2012 1:19 PM To: "Oliver Garraux" <oliver@g.garraux.net>, nanog@nanog.org Subject: Re: job screening question On 7/5/2012 1:11 PM, Oliver Garraux wrote: that.

Could HR be mangling the question or something?

Oliver

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Oliver Garraux Check out my blog: www.GetSimpliciti.com/blog Follow me on Twitter: twitter.com/olivergarraux

On Thu, Jul 5, 2012 at 1:02 PM, William Herrin <bill@herrin.us> 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@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> 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