filtering results to subnets

[Jerome Haltom]

I have a desire to filter A records returned to clients that are outside
of certain subnets. Basically my zone has a lot of private addresses in
it. I'm cool with this.

I'd like those private addresses to only be sent to other private
addresses. Any non private address should not receive them.

I know views is an option for this. The problem there is I actually have
to maintain two zones. This is actually a slave zone from an Active
Directory server, where host records come and go all the time,
automatically, and which I'm not going to manipulate into a view by
hand. I also don't mind AXFR's and IXFR's returning the private
addresses.

If such a feature does not exist, does anybody have any opinions about
the potential to add such a feature? I'd envision a syntax like
sortlist:

filter
{
	{
		0/0;
		{
			!192.168.0.0/16;
		};
	};
	{
		192.168.0.0/16;
		{
			192.168.0.0/16;
		};
	};
};

Or something.