[Dshield] DNSBL

[Tom]

At 9:56 AM -0400 7/10/07, Rick Leir wrote:
>list-request at lists.dshield.org wrote:
>
>  > list.dsbl.org, dul.dnsbl.sorbs.net, zen.spamhaus.org and
>  > combined.njabl.org. Of these, demonstrably dul and list block against
>  > dynamically assigned ranges.
>
>  > I have to say that I'm wildly, ecstatically, enthusiastic about the
>  > results from these blocks, up to 1500 a day. I monitor refused mail
>  > closely, every day (and have done for the past 4 years), and have to
>  > now seen not one false positive from these DNSBLs - YMMV.
>
>1/ Your efforts are commendable.  Most admins are not able to put that
>much effort into it.
>
>2/ False positives are needles in a haystack, laborious to identify.

Actually not so hard especially if you provide an informative error response.

>3/ If a system depends on labour at the level you have exerted, I am
>sorry to say, it is in general sure to fail.  We will have to put up
>with a nonzero rate of false positives.

zen.spamhaus.org is extremely reliable, imho, as is rejecting on no 
PTR records and on a MAIL FROM that does not have valid entry (per 
2821)

Tom
-- 

Tom Shaw - Chief Engineer, OITC
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