We just started something I've been thinking about for a while:  Negative weight tests to offset specific test failures for well-known domains.  For example, a large number of false positives we see are from Earthlink, Mindspring, Sprint, Verizon, etc.
 
Now you may be thinking, of course, these are large providers with dial-up user bases, so you would expect a large percentage of false positives to be from them...but hold on a minute.  Many of these large domains are being penalized in our system for routing or not having abuse@ or postmaster@ addresses.  Almost all of these would not have ended up in the hold queue if they had not been so penalized...thus the idea to figure out a manageable way to NOT penalize them for these technical RFC violations.
 
So, what we've done is to start filters to counteract the weights for major tests that a few of these domains fail.  By doing it specifically for a particular domain, we reduce false positives but avoid losing the effectiveness of the test on other domains.
 
Anyway, attached zip are the filter files.  As I mentioned, they have just been started, so there are just a few domains in them at present.  At the top of the filter file are suggested guidelines on how to use them.  There are probably better ways to handle this, so I welcome comments/feedback.

Darin.
 
 
# 
------------------------------------------------------------------------------------------------
# Filter Name:  n_ROUTING
# Author:       Darin Cox
# Date:         4/14/2005
# Description:  Used to negate the weight of the ROUTING test for select domains
#
# Notes:        Recommended config is to negative weight this test to 
#               exactly offset the ROUTING test.  For example, if you have 
#
#               ROUTING         spamrouting             x                       
x       125     0
#
#               Then this test is recommended to be added as
#
#               n_ROUTING       filter  C:\{MAILSERVER}\Declude\n_ROUTING.txt   
x       -125    0
#
# 
------------------------------------------------------------------------------------------------

# Don't run the test unless the email failed the ROUTING test
TESTSFAILED END NOTCONTAINS ROUTING

MAILFROM        END     ENDSWITH        mail.sprint.com
# 
------------------------------------------------------------------------------------------------
# Filter Name:  n_NOABUSE
# Author:       Darin Cox
# Date:         4/14/2005
# Description:  Used to negate the weight of the NOABUSE test for poorly
#               administered domains from which we still need to accept mail
#
# Notes:        Recommended config is to negative weight this test to 
#               exactly offset the NOABUSE test.  For example, if you have 
#
#               NOABUSE         rhsbl   abuse.rfc-ignorant.org          
127.0.0.4       20      0
#
#               Then this test is recommended to be added as
#
#               n_NOABUSE       filter  C:\{MAILSERVER}\Declude\n_NOABUSE.txt   
x       -20     0
#
# 
------------------------------------------------------------------------------------------------

# Don't run the test unless the email failed the NOABUSE test
TESTSFAILED END NOTCONTAINS NOABUSE

MAILFROM        END     ENDSWITH        earthlink.net
MAILFROM        END     ENDSWITH        mail.sprint.com
MAILFROM        END     ENDSWITH        mindspring.com
MAILFROM        END     ENDSWITH        verizon.com
# 
------------------------------------------------------------------------------------------------
# Filter Name:  n_NOPOSTMASTER
# Author:       Darin Cox
# Date:         4/14/2005
# Description:  Used to negate the weight of the NOPOSTMASTER test for poorly 
#               administered domains from which we still need to accept mail
#
# Notes:        Recommended config is to negative weight this test to 
#               exactly offset the NOPOSTMASTER test.  For example, if you have 
#
#               NOPOSTMASTER    rhsbl   abuse.rfc-ignorant.org                  
127.0.0.3       25      0
#
#               Then this test is recommended to be added as
#
#               n_NOPOSTMASTER  filter  
C:\{MAILSERVER}\Declude\n_NOPOSTMASTER.txt      x       -25     0
#
# 
------------------------------------------------------------------------------------------------

# Don't run the test unless the email failed the NOPOSTMASTER test
TESTSFAILED END NOTCONTAINS NOPOSTMASTER

MAILFROM        END     ENDSWITH        verizon.com

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