RE: [Exim] Howto block all unknown/unlisted user?

On Mon, 2004-03-15 at 07:16 -0500, Dickenson, Steven wrote:
> It's possible that he's running a relay server, in which case the default
> configuration will not suffice. You can use LDAP lookups against your
> internal mail server if that's possible, or output a textfile of valid
> local_parts from the internal server and do a lookup against that.

Recipient verification callouts may also work, but be careful. Obviously
if you don't use defer_ok you lose the whole point of being an MX
backup. Also, because Exim uses MAIL FROM:<> in the callout instead of
the real $sender_address of the mail in question, you may wrongly reject
mail if some addresses (like mailing lists) at the target domain don't
accept bounces but _would_ have accepted non-bounce mail.

--
dwmw2