On Fri, Jun 17, 2011 at 10:46:53PM +0200, [email protected] wrote:
> postscreen_dnsbl_sites = cbl.abuseat.org*2, bl.spamcop.net*1,
> b.barracudacentral.org*2 ,zen.spamhaus.org*3 ,sbl.spamhaus.org*2,
> xbl.spamhaus.org*2
> postscreen_dnsbl_threshold = 2
You have no fewer than four useless lookups in the above. A Zen
lookup includes SBL and XBL, and XBL includes CBL. This is all
unnecessary load on the DNSBL nameservers, and gains you nothing.
With postscreen_dnsbl_threshold = 2, your Spamcop lookup is also
useless. If any other DNSBL returns positive, your threshold score
will be reached. And there are no other 1-point lookups that could
join with Spamcop and reach the threshold.
What you have in the quoted lines is functionally equivalent to:
postscreen_dnsbl_sites = b.barracudacentral.org,zen.spamhaus.org
leaving postscreen_dnsbl_threshold at the default value of 1.
Soon I will be putting up a web page with slides and notes for my
postscreen talk at Southeast (USA) LinuxFest. In the meantime, you
can see what I have posted about my postscreen config here:
http://permalink.gmane.org/gmane.mail.postfix.user/218114
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