[dns-operations] PMTUD of .org servers

Paul Vixie vixie at isc.org
Sat Jun 20 14:20:07 UTC 2009

> From: Michael Graff <mgraff at isc.org>
> Date: Sat, 20 Jun 2009 08:34:07 -0500
> Pmtu requires that the thing sending data use the pmtu feedback. With  tcp
> this happens in the kernel. With UDP it happens in the application.
> Do any servers actually ask the os for this feedback or process the  icmp
> messages?

when i wrote RFC 2671 i don't know what i was thinking for the part about
"advertised buffer size should take pmtu into consideration" since the need
is for a buffer of a certain size (for dnssec metadata for example) and no
guideance is given in RFC 2671 as to avoiding fragmentation if possible.

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