>If your smarthost does indeed perform recipient callout and requires
>AUTH for you to relay, then I don't know what you can do (unless you
>can bypass the smarthost).
the ISP hosts a lot of domains, which send us spam with faked
addresses.
The callout verification is done based on sender domains.
>sorry but I am not sure I understand. If you do callout you are
>effectively testing if a bounce is deliverable. If you are using a
>smarthost, then unless that uses recipient callout to test what you
>are passing to it, then your callout will always succeed (as long as
>you are authorised relaying through it).
Currently no callout succeeds, and I know about the problem with a
smarthost.