[154517] in North American Network Operators' Group
Re: job screening question
daemon@ATHENA.MIT.EDU (William Herrin)
Thu Jul 5 13:42:49 2012
In-Reply-To: <CAFANWtWgFV7Mg1rdLctGgHmtCNGUxNdn5pATNzhTW3vXOHP8vw@mail.gmail.com>
From: William Herrin <bill@herrin.us>
Date: Thu, 5 Jul 2012 13:41:42 -0400
To: Darius Jahandarie <djahandarie@gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Thu, Jul 5, 2012 at 1:20 PM, Darius Jahandarie <djahandarie@gmail.com> wrote:
> On Thu, Jul 5, 2012 at 1:11 PM, Oliver Garraux <oliver@g.garraux.net> wrote:
>> Seems fairly straightforward to me. It'll break path MTU discovery.
>
> Since Bill said "(not IP in general, TCP specifically)", I don't think
> PMTUD breaking is what he's looking for.
No, path MTU discovery is the answer I'm fishing for. The stack
notifies TCP of the fragmentation needed message and TCP handles it
within the TCP stack. Managing path MTU discovery is specific to each
layer-4 protocol even if the trigger message (destination unreachable,
fragmentation needed but DF set) is the same.
If a candidate gives me a more clever answer, I'd take that too. :-)
"This would block all IP traffic." is not a correct answer. It's not
even a naively incorrect answer.
Regards,
Bill Herrin
--
William D. Herrin ................ herrin@dirtside.com bill@herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004
