No spam???

[Lowell Gilbert]

cpghost <cpghost at cordula.ws> writes:

> On Tue, Jan 15, 2008 at 08:48:32AM -0500, John Almberg wrote:
>> I've been doing some more digging since my last post, and have figured out 
>> that the spam is not being blocked by pf, as I suspected (since it wasn't 
>> showing up in my spam folder), but by spamassassin blacklists.
>> 
>> The smtp log file has lots of entries like:
>> 
>> 2008-01-14 09:30:37.074087500 rblsmtpd: 123.20.89.67 pid 72121: 451 
>> http://www.spamhaus.org/query/bl?ip=123.20.89.67
>> 2008-01-14 09:31:05.271514500 rblsmtpd: 58.227.241.97 pid 72122: 451 
>> Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?58.227.241.97
>> 2008-01-14 09:31:17.404943500 rblsmtpd: 41.196.155.56 pid 72123: 451 
>> http://www.spamhaus.org/query/bl?ip=41.196.155.56
>> 2008-01-14 09:31:18.304682500 rblsmtpd: 123.20.89.67 pid 72124: 451 
>> http://www.spamhaus.org/query/bl?ip=123.20.89.67
>> 
>> So raises the same point that Oliver makes: how trustworthy are these 
>> blacklists?
>
> YMMV, of course!
>
> I'm using spamhaus.org's blacklists for quite some time (many years)
> to block spam in postfix and they've been VERY trustworthy so far.
>
> But I can't say the same for the others, which seem occasionally a
> little bit too eager/aggressive and accumulate way too many false
> positives.

The OP was using spamassassin, which can score a mail as more likely
to be spam based on an RBL. This makes even an untrustworthy RBL
useful while still protecting yourself against its mistakes.

For example, I use spamhaus blacklists in postfix myself, but I let
messages come in from SORBS-blacklisted sites.  Then the messages will
get a point or two (of 4 or 5 needed to be marked as spam) as a result
of the SORBS blacklist.

At least, I think I've got the list names correct; I haven't touched
my configurations for either postfix or spamassassin in quite a while.