Quoting Philip Hazel <ph10@???>:
> > just talking into the wild, as i haven't yet come to touch v4, what
> > about adding a final router that just :fail:s ?
>
> Exactly.
>
> cant_route:
> driver = redirect
> allow_fail
> data = :fail: Unknown local part
Wouldn't it be better to restrict that router to local domains only? You
don't want to look like you treat a remote address as local if one ever
reaches that router.