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On 7.1.2016 12:37, BIND Feature Requests via RT wrote:
> 
> Greetings,
> 
> This message has been automatically generated in response to the
> creation of a trouble ticket regarding:
> 	"auto-disable empty zones if forward 'first' is configured", 
> a summary of which appears below.
> 
> There is no need to reply to this message right now.  Your ticket has been
> assigned an ID of [ISC-Bugs #41441].
> 
> Please include the string:
> 
>          [ISC-Bugs #41441]
> 
> in the subject line of all future correspondence about this issue. To do so, 
> you may reply to this message.
> 
>                         Thank you,
>                         bind-suggest@isc.org
> 
> -------------------------------------------------------------------------
> Hello,
> 
> I would like to propose a change in BIND's behavior with respect to
> interaction between forward 'zones' and automatic empty zones:
> 
> Currently the configure_view() in server.c disables/skips the automatic empty
> zones if there is a forward 'zone' with policy 'only'.
> 
> 	/*
> 	 * If we would forward this name don't add a
> 	 * empty zone for it.
> 	 */
> 	result = dns_fwdtable_find(view->fwdtable, name,
> 				   &forwarders);
> 	if (result == ISC_R_SUCCESS &&
> 	    forwarders->fwdpolicy == dns_fwdpolicy_only)
> 		continue;
> 
> For me as a user, it is kind of confusing and inconvenient that empty zones
> are enabled even for dns_fwdpolicy_first, because it effectively means that
> forwarding is not working for automatic empty zones.
> 
> Typically I have to manually disable empty zones when global forwarder (for
> root zone) is configured as traffic optimization measure, while full recursion
> is used as a fallback.
> 
> In other words, the gotcha is that condition 'we would forward this name' is
> fulfilled also when forward policy 'first' is used.
> 
> 
> Would it be possible to relax the condition to
>     forwarders->fwdpolicy != dns_fwdpolicy_none
> ?
> 
> That would match my expectation as user - i.e. when I configure forwarding for
> all zones, it should be respected.
> 
> 
> I can see the potential problem with leaking queries when all configured
> forwarders fail, but given that this would happen only in a (hopefully rare)
> error state, I think it is a good trade-off for usability.
> 
> 
> If this is 'simple' fix is not acceptable, I can write a patch which would
> replace automatic empty zone with forward 'zone' with policy 'only' and
> addresses taken from parent forward zone with policy 'first', if you wish.
> 
> 
> Thank you for considering this.

I found out that the original version was not complete. Here is new version of
the patch + test.

-- 
Petr Spacek  @  Red Hat