check hosts = +ignore_unknown : *.$sender_address_domain : $sender_address_domain : ${lookup dnsdb{>:defer_never,mxh=$sender_address_domain}}
search_open: dnsdb "NULL"
search_find: file="NULL"
check hosts = +ignore_unknown : *.$sender_address_domain : $sender_address_domain : ${lookup dnsdb{>:defer_never,mxh=$sender_address_domain}}
search_open: dnsdb "NULL"
search_find: file="NULL"