[dns-operations] PMTUD of .org servers

Paul Vixie vixie at isc.org
Fri Jun 19 03:02:42 UTC 2009

> From: Mark Andrews <marka at isc.org>
> Date: Fri, 19 Jun 2009 11:08:27 +1000
> 	Linux and Solaris set DF by default.  Linux boxes allow it
> 	to be modified on a per-socket basis.  On Solaris boxes it
> 	is a global flag.  You can't disable DF on UDP without also
> 	disabling DF on TCP.
> 	Other boxes that implement path mtu discovery appear to only
> 	do it on TCP connections by default.
> 	Named turns off the setting of DF for UDP on all platforms
> 	where we are aware of a per socket control.
> 	Setting DF on UDP/DNS responses is detrimental to DNS.

so solaris basically can't be a good edns server, period, full stop?

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