Re: [exim-dev] feature request for exim: query DNSBL provide…

On 2017-09-12 at 09:45 +0100, Jeremy Harris wrote:
> On 11/09/17 23:35, Phil Pennock wrote:
> > So there's some value in having an optional, EXPERIMENTAL_FOO feature,
> > for more advanced DNS handling.
>
> As an alternate implementation, a standard (but custom-configured)
> resolver packaged with Exim in a container?
>
> Would that suffice, or would the libresolv API still be insufficiently
> rich to do the Very Handy odd queries forseen fr apam-fighting?

Probably suffice for Rob, but the point around the "NS above the cut" is
that it's something no normal resolver ever asks for. The libresolv
portable API provides no interface for choosing which IPs to send
messages to.

It's easy enough in Go, Python, Perl although in no case with the core
language or stdlib, only with "very common" ecosystem libraries. For C,
we'd be looking at the same solution. The people who created the getdns
API know what they're doing and so it's solidly worthy of consideration,
but I haven't done anything with it to be able to endorse it as "the
right way". Only "the way I kept meaning to find time to look at."

-Phil