Thank you for the reply. I removed RBL control on SMTP tab and now I control RBL in uriRBL and preRBL modules. Now I have 5 active modules in the anti-spam configuration. They're UriRBLs, NeceBayes, ClamSpam, PreRBLs and Spamc.
In the preRBLs module I'm using only zen.spamhaus.org as rbl server and I set list hits to be spam at 3 not avoiding SPF checking.
Now I have two problems.
1. I have to remove the reverse DNS check on smtp checks because it keep blocking email that I want to get in. This make a lot of unwanted email to get accepted too. I tryed to insert the hosts in the "don't check these hosts" box (to get email from name@address.ext I put address.ext in the box) but it seem not to work. I'm doing right here?
2. On the trace of some email I found under the Filtering Engine part this: "Jun 25 09:51:05 localhost MailScanner[2068]: Found phishing fraud". This email seems to be phishing also at my eyes but the mail went through the antispam filter without any problem. How can I set the phishing block?