nanog mailing list archives
Re: job screening question
From: Randy <randy_94108 () yahoo com>
Date: Thu, 5 Jul 2012 16:01:49 -0700 (PDT)
--- On Thu, 7/5/12, William Herrin <bill () herrin us> wrote:
From: William Herrin <bill () herrin us> Subject: Re: job screening question To: "Derek Andrew" <Derek.Andrew () usask ca> Cc: "nanog () nanog org" <nanog () nanog org> Date: Thursday, July 5, 2012, 3:18 PM On Thu, Jul 5, 2012 at 5:05 PM, Derek Andrew <Derek.Andrew () usask ca> wrote:You implement a firewall on which you blockall ICMP packets. Whatpart of the TCP protocol (not IP in general,TCP specifically)malfunctions as a result?Isn't MTU discovery on IP and not TCP?If you want to overthink the question, the failure in the TCP protocol is that it doesn't adjust the MSS to match the path MTU. It continues to rely on the incorrect path MTU estimate, sending too-large packets which will never arrive. This happens because TCP doesn't receive a notification that the path MTU estimate has changed from the default because the lower layer PMTUD algorithm never receives the expected ICMP packet. This is, incidentally, is a detail I'd love for one of the candidates to offer in response to that question. Bonus points if you discuss MSS clamping and RFC 4821. The less precise answer, path MTU discovery breaks, is just fine. Regards, Bill Herrin
Precisely! and if I understand correctly, a non-techinical person within HR is expected to hear this answer and relay it to you? That is more than a long shot. Unless of course they have photographic memories, are great typists or perhaps do "short hand". ./Randy
Current thread:
- RE: job screening question, (continued)
- RE: job screening question Terry Baranski (Jul 05)
- Re: job screening question Ray Soucy (Jul 05)
- Re: job screening question Leo Bicknell (Jul 05)
- Re: job screening question David Coulson (Jul 05)
- Re: job screening question William Herrin (Jul 05)
- Re: job screening question David Coulson (Jul 05)
- Re: job screening question Scott Howard (Jul 05)
- Re: job screening question William Herrin (Jul 05)
- Re: job screening question Ray Soucy (Jul 05)
- Message not available
- Re: job screening question Derek Andrew (Jul 05)
- Re: job screening question William Herrin (Jul 05)
- Re: job screening question Randy (Jul 05)
- Re: job screening question William Herrin (Jul 05)
- Re: job screening question Owen DeLong (Jul 05)
- Re: job screening question Derek Andrew (Jul 05)
- Re: job screening question Jason Baugher (Jul 05)
- Re: job screening question Mike Hale (Jul 05)
- Re: job screening question Jon Lewis (Jul 05)
- Re: job screening question Owen DeLong (Jul 05)
- Re: job screening question William Herrin (Jul 05)
- Re: job screening question George Herbert (Jul 05)
- Re: job screening question Jon Lewis (Jul 05)
- Re: job screening question William Herrin (Jul 05)