Amedeo Rinaldo:
> But i've (obviously) noticed an high increase in dns queries (unbound
> local resolver) and checking my logs i've realized that about 80% of
> 'defer/reject' would be done by less expensive tests (not rbl
> dependent). Consider that at the end of my 'accept-chain' i've postfwd2
Why do you believe that postscreen DNSBL lookups are expensive?
They happen in parallel; there are no extra delays.
You can't compare postscreen lookup with smtpd DNSBL lookups. The
lookups by smtpd happen sequentially and for one client at a time
and increase the length of an SMTP session, making Postfix more
vulnerable to overload problems.
With postscreen, DNSBL lookups happen in parallel and for multiple
clients the same time, and making Postfix less vulnerable to overload
problems.
Wietse
