If your primary MX is down - then the callout will always fail, will it
not? So all e-mail would be (temporarily) rejected from your backup mx's,
which is not what you have backup mailservers for.
Giuliano Gavazzi <eximlists@???> wrote in
news:a06001204bb1dbc8723ad@???:
> or a recipient callout:
>
> verify = recipient/callout
>
> but only for incoming messages.