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Re: TCP and IPV6_USE_MINMTU

Mark Andrews <marka@isc.org> Fri, 16 October 2015 22:57 UTC

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To: Brian E Carpenter <brian.e.carpenter@gmail.com>
From: Mark Andrews <marka@isc.org>
References: <20151016034110.306563A939AB@rock.dv.isc.org> <20151016202620.GI1442@verdi> <20151016203155.3D2473AA8817@rock.dv.isc.org> <56217BAB.2040608@gmail.com>
Subject: Re: TCP and IPV6_USE_MINMTU
In-reply-to: Your message of "Sat, 17 Oct 2015 11:35:23 +1300." <56217BAB.2040608@gmail.com>
Date: Sat, 17 Oct 2015 09:56:55 +1100
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In message <56217BAB.2040608@gmail.com>, Brian E Carpenter writes:
> On 17/10/2015 09:31, Mark Andrews wrote:
> > 
> > In message <20151016202620.GI1442@verdi>, John Leslie writes:
> >> Mark Andrews <marka@isc.org> wrote:
> >>>
> >>> Please see
> >>> https://www.ietf.org/id/draft-andrews-tcp-and-ipv6-use-minmtu-00.txt
> >>>
> >>> It addresses what should be obviously done but isn't by many
> >>> implementations.
> >>
> >>    Alas, this draft gives no clue _how_ to check IPV6_USE_MINMTU ...
> >> (or, for that matter, how to set it).
> >>
> >>    One could reasonably guess that s/he should look through RFC3542 to
> >> find how to check this; but RFC3542 contains no such string. (It does
> >> contain the string IPV6_USE_MIN_MTU; but I don't feel justified in
> >> guessing that far astream...
> 
> Incidentally, it recently came to my attention that standard Python
> doesn't support RFC3542. I don't know how widespread that issue is, but
> it may be behind some of these broken MSS deployments.
> 
>     Brian

The entire advanced socket API is poorly supported because POSIX
didn't pick it up.

That said I've updated the document based on the feedback received
to date.

https://tools.ietf.org/html/draft-andrews-tcp-and-ipv6-use-minmtu-03

> > Yes, I typo'd that, repeatedly.
> >  
> >>    Perhaps adding a citation to the specific section of a particular
> >> RFC would help?
> >>
> >> --
> >> John Leslie <john@jlc.net>
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org

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