From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: UDP path MTU discovery
Date: Mon, 29 Mar 2010 23:29:12 +0200
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Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
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To: Rick Jones <rick.jones2@hp.com>
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Le lundi 29 mars 2010 =C3=A0 14:01 -0700, Rick Jones a =C3=A9crit :

> I would get the alphabet soup completely garbled, but the DNS folks a=
re talking=20
> about EDNS (?) message sizes upwards of 4096 bytes - encryption/authe=
ntication=20
> and other angels being asked to dance on the head of the DNS pin are =
asking for=20
> more and more space in the messages.
>=20
> So, someone will have to blink somewhere - either DNS will have to go=
 TCP and=20
> *possibly* take RTT hits there depending on various patch streams, or=
 the IEEE=20
> will have to sanction jumbo frames and people deploy them widely, or =
it will=20
> have to become feasible to actually do the occasional IPv6 datagram=20
> fragmentation and get a timely retransmission out of a UDP applicatio=
n on a PMTU=20
> hit.
>=20

1) 4096 bytes UDP messages... well...
2) Using regular TCP for DNS servers... well...

I believe some guys were pushing TCPCT (Cookie Transactions) for this
case ( http://tools.ietf.org/html/draft-simpson-tcpct-00.html )

(That is, using an enhanced TCP for long DNS queries... but not only fo=
r
DNS...)