LOCAL_CONFIG
# database of known spammers
Kspammers hash /etc/mail/spammers

LOCAL_RULESETS
Scheck_mail

# check for valid domain name (incompatible with DeliveryMode=defer)
R$*			$: <?> $>3 $1			make domain canonical
R<?> $* < @ $+ . >	$: <OK>				tag resolved names
R<?> $* < @ $+ >	$#error $: 451 Domain must resolve

# check relay against spammers database
R$*			$: $(spammers $&{client_name} $: OK $)
ROK			$@ OK
R$+			$#error $: 551 $1