Thanks, We succeeded to solve this problem in this way, I create in main.cf
smtpd_client_restrictions = check_sender_access hash:/etc/postfix/check_bounce_sender, cat /etc/postfix/check_bounce_sender <> check_no-bounce_domains And: smtpd_restriction_classes = bloqueio-reverso, check_no-bounce_domains bloqueio-reverso = reject_unknown_client check_no-bounce_domains = check_client_access hash:/etc/postfix/nobounce_domains cat /etc/postfix/nobounce_domains google.com DISCARD Bounce_Attack Mar 12 16:18:51 servername postfix/smtpdmx[28290]: NOQUEUE: discard: RCPT from mail-ew0-f163.google.com[209.85.219.163]: <mail-ew0-f163.google.com[209.85.219.163]>: Client host Bounce_Attack; from=<> to=<lo...@mydomain> proto=ESMTP helo=< mail-ew0-f163.google.com> If i have problems with another ISP what i have to do is add a domain in /etc/postfix/nobounce_domains . Thanks, Alexandre Carlim 2009/3/12 Alexandre Carlim <alexandrecar...@gmail.com> > Hi, > > What i have to do for discard email when reverse name is google.com and > from is <> , Currently i''m receive 1.200 millions for email per seconds, a > bounce atack. > > Thanks > Alexandre Carlim >