9.2.1 and allow-v6-synthesis

[Mark_Andrews at isc.org]

> > > The odd thing was that even lookups which allow-v6-synthesis should
> > > have had no impact on became very slow ("dig A salmon.maths.tcd.ie"
> > > timed out most of the time).
> 
> > 	Just sounds like the server is under powered / swapping for
> > 	the load being put on it.  
> 
> It usually doesn't break a sweat (0.5% CPU, machine has 1GB of RAM,
> no swapping).
> 
> > 	The code that starts the v6 synthesis process shouldn't put
> > 	a load on other queries unless you have a complicated
> > 	acl.
> 
> The ACL being used is the recursive-clients one, defined below. This
> is set for the allow-recursion and allow-v6-synthesis options.

	Well you you could use "any;" for the allow-v6-synthesis.
	allow-v6-synthesis only applies to those that have already
	passed allow-recursion.

> It sounds like I don't have enough info to debug the problem, so
> I'll try to reproduce it in a test environment. I do have the output
> of a "named -d 3 -f -g" while the problem was happening, if anyone
> is interested in decoding it for me.
> 
> 	David.
> 
> acl real-localhost { 127.0.0.1; ::1; };
> acl tcd {
> 	134.226.0.0/16;
> 	193.1.64.0/21; 193.1.67.0/24; 193.1.68.0/24; 193.1.69.0/24;
> 	2001:770:10::/80; fe80::/16;
> };
> acl recursive-clients {
> 	real-localhost; tcd;
>         160.6.0.0/16; 143.117.147.0/24; 143.117.41.11; 143.117.143.18;
> };
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org