-------- Original-Nachricht --------
> Datum: Fri, 31 Jul 2009 10:00:47 -0700
> Von: "Michael Watkins" <[email protected]>
> An: [email protected]
> Betreff: Re: [Dspam-user] RBL Configuration

> On Fri, July 31, 2009 09:07, Steve wrote:
> > I use RBL and other mechanism here with great success and with 0 false
> positive rate (related to RBLs) since years. But I am not trusting one
> single RBL. Never ever would I do that! I would suggest you to look for
> something like policyd-weight and/or postfwd and combine a bunch of
> RBL/RHBL/WHL and other mechanism to mitigate the failure of one single
> lookup list.
> 
> For postfix users, I would second, without any reservation whatsoever, the
> use of policyd-weight. No one RBL will cause a block; you can add others
> to the default configuration as you desire.
> 
> You'll find that you are blocking a huge amount of spam *before it hits
> your mail queue*, which means a massive reduction in server resources used
> (less work for dspam) not to mention more or less eliminating problems
> like rejection notice bounce back and the like.
> 
> A single perl script and one configuration file - nothing could be easier.
> Is in FreeBSD ports if you are a user of that OS or direct from the web
> site.
> 
> I've customized the script somewhat; I don't allow certain conditions to
> pass as readily, and I've integrated a patch which allows Geo IP lookups.
> As our users do not do much business with certain spam producing haven
> countries (notably VN, BR, CN), I set the bar high for mail senders in
> that country - guilty until proven innocent, as opposed to the default,
> innocent until proven guilty.
> 
That Geo-IP patch you are talking about can be easy avoided. Just use stock 
policyd-weight and DNSBL functionality to increase score for them.
If you are from Europe then you could use lookups to *.countries.nerd.dk and 
all others could use lookups to *.countries.blackholes.us.

So in your case I would use:
# Give a better score to our Canadian mail servers
 'ca.countries.nerd.dk', -1.00,  0.00, 'NERD-CA',

# Set the bar higher for some high-rate spam countries
 'vn.countries.nerd.dk',  0.00,  2.00, 'NERD-VN',
 'br.countries.nerd.dk',  0.00,  2.00, 'NERD-BR',
 'cn.countries.nerd.dk',  0.00,  2.00, 'NERD-CN',


No need to patch policyd-weight to allow Geo-IP lookups and the other positive 
effect is that DNS uses very low bandwidth and can be locally cached. :)

But it does not stop here. Wanting to set the bar high for certain ASN? No 
problem (just an example):
 'AS5617.rbl.cluecentral.net',   2.500,    0.00, 'AS5617',  # Telekomunikacja 
Polska S.A.
 'AS4134.rbl.cluecentral.net',   1.606,    0.00, 'AS4134',  # CHINANET-BACKBONE 
No.31,Jin-rong Street
 'AS4766.rbl.cluecentral.net',   0.615,    0.00, 'AS4766',  # KIXS-AS-KR Korea 
Telecom
 'AS4837.rbl.cluecentral.net',   0.382,    0.00, 'AS4837',  # CHINA169-BACKBONE 
CNCGROUP China169 Backbone
 'AS4814.rbl.cluecentral.net',   0.380,    0.00, 'AS4814',  # CHINA169-BBN 
CNCGROUP  IP network China169 Beijing Broadband Network
 'AS3269.rbl.cluecentral.net',   0.363,    0.00, 'AS3269',  # ASN-IBSNAZ 
TELECOM ITALIA
 'AS17858.rbl.cluecentral.net',  0.328,    0.00, 'AS17858', # KRNIC-ASBLOCK-AP 
KRNIC
 'AS4755.rbl.cluecentral.net',   0.315,    0.00, 'AS4755',  # VSNL-AS Videsh 
Sanchar Nigam Ltd. Autonomous System
 'AS9394.rbl.cluecentral.net',   0.230,    0.00, 'AS9394',  # CRNET CHINA 
RAILWAY Internet(CRNET)
 'AS17849.rbl.cluecentral.net',  0.215,    0.00, 'AS17849', # GINAMHANVIT-AS-KR 
hanvit ginam broadcasting comm.
 'AS8075.rbl.cluecentral.net',   0.201,    0.00, 'AS8075',  # 
MICROSOFT-CORP---MSN-AS-BLOCK - Microsoft Corp
 'AS9121.rbl.cluecentral.net',   0.108,    0.00, 'AS9121',  # TTNET TTnet 
Autonomous System
 'AS24138.rbl.cluecentral.net',  0.108,    0.00, 'AS24138', # 
CRNET_BJ_IDC-CNNIC-AP China Tietong Telecommunication Corporation
 'AS4788.rbl.cluecentral.net',   0.102,    0.00, 'AS4788',  # TMNET-AS-AP TM 
Net, Internet Service Provider
 'AS7132.rbl.cluecentral.net',   0.094,    0.00, 'AS7132',  # SBIS-AS - SBC 
Internet Services
 'AS14780.rbl.cluecentral.net',  0.094,    0.00, 'AS14780', # INKTOMI-LAWSON - 
Inktomi Corporation
 'AS12424.rbl.cluecentral.net',  0.093,    0.00, 'AS12424', # JAZZASN 
Autonomous System
 'AS8346.rbl.cluecentral.net',   0.074,    0.00, 'AS8346',  # SONATEL-AS 
Autonomous System
 'AS9318.rbl.cluecentral.net',   0.068,    0.00, 'AS9318',  # HANARO-AS Hanaro 
Telecom Inc.
 'AS7470.rbl.cluecentral.net',   0.066,    0.00, 'AS7470',  # ASIAINFO-AS-AP 
ASIA INFONET Co.,Ltd.
 'AS3786.rbl.cluecentral.net',   0.060,    0.00, 'AS3786',  # ERX-DACOMNET 
DACOM Corporation


Again. No need for patching. Just creative usage of the available 
functionality. :)

But I have as well patched my policyd-weight. Added p0f integration, additional 
sender based reputation lookups, S25R rules, etc... It's kind of hard to not 
patch since Robert has stopped developing it any further.


> All in all policyd-weight is a simple and hugely effective tool. So
> effective that I can shut off dspam if need be and for the most part, many
> users would not even notice.
> 
Same here.


> In fact for our purposes, the only thing dspam is used for is tagging (and
> integrated clamav scanning). That in no way diminishes dspam's value to
> us... the tagging feature (with delivery) is important to us.
> 
> What little spam makes its way through the postfix / policyd-weight
> gauntlet I do want tagged, but delivered (dovecot sieve places this
> potential spam in a junk dir), and that's dspam's mission for us.
> 
> 
// Steve
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