+SECTION(acl, misc)m4_dnl
+mail_check_sender:
+
+ ## See whether there's a special exception for this sender domain.
+ accept senders = ${LOOKUP_DOMAIN($sender_address_domain,
+ {KV(senders, {$value}{})},
+ {})}
+
+ ## Ensure that the sender is routable. This is important to prevent
+ ## undeliverable bounces.
+ require message = Invalid sender; \
+ ($sender_verify_failure; $acl_verify_message)
+ verify = sender
+
+ ## We're good, then.
+ accept
+