Re: compiling with c-ares seems to break os x domain resolution?

On Wed, 15 Jan 2020, Cole Varner via curl-library wrote:

> When run in isolation, this build of cURL failed to resolve an internal host
> using the VPN DNS.

...

> Wondering if anyone can shed some light on how curl handles domain
> resolution and why it would fail when built with c-ares?

Hi Cole,

Name resolving in modern systems is complicated. If it would've been just DNS
to deal with, things would've been so much easier. Instead there are lots of
additional ways to resolve names to addresses, some that are specific to
certain operating systems and some that are more vaguely defined and hard to
mimic in replacement libraries.

If a host name resolves with the system resolver and not with c-ares, that's
an issue for c-ares. curl just passes the name to whatever resolver library it
uses and it relies on that library to do the job.

Replacing the stock resolver functionality with a replacement library like
c-ares, is unfortunately bound to lead to occasional edge cases where they
differ. You seem to have found such a one. I know c-ares developers do their
best in trying to make sure that c-ares can work as a full replacement
resolver, and I'm sure they'll work with you in order to try to fix this case
as well if you take it there. Assuming you've tried this with a reasonably
modern c-ares version.

Disclaimer: I'm still a c-ares maintainer but I'm trying to reduce my
activities in that project (due to lack of time and focus).

-- 
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