> x@y is undeliverable: unrouteable mail domain "y"
    <-- x%y@testhack.test.ex
> x%y@test.ex
  router = local_domains, transport = local_delivery
> x@y is undeliverable: unrouteable mail domain "y"
    <-- x%y%testhack2.test.ex@testhack.test.ex
> X@test.ex
    <-- X%test.ex@testhack.test.ex
  router = local_domains, transport = local_delivery
>