Commit cbc2a71c2 makes `connect` syscall fail fast when a container is
only attached to an internal network. Thanks to that, if such a
container tries to resolve an "external" domain, the embedded resolver
returns an error immediately instead of waiting for a timeout.
This commit makes sure the embedded resolver doesn't even try to forward
to upstream servers.
Co-authored-by: Albin Kerouanton <albinker@gmail.com>
Signed-off-by: Rob Murray <rob.murray@docker.com>
790c3039d0