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Re: [Asrg] 7. Best Practices - DNSBLs - Article

2003-08-12 17:43:37

We (SpamAssassin) measure FP/FN rates for DNSBLs as part of our rescoring
process.   However the results aren't prettified for the web.  Maybe
sometime soon.

Scroll down on this page:

  http://useast.spamassassin.org/dist/rules/STATISTICS-set1.txt

and take a look at the effectiveness ratings there. e.g.

OVERALL%   SPAM%     HAM%     S/O    RANK   SCORE  NAME
 39.058  56.1503   0.2042    0.996   0.98    1.10  RCVD_IN_DSBL

that means the dsbl.org BL hit 56% of spam, 0.2% of nonspam, which is an
effectiveness rate of 99.6% accuracy.  (RANK and SCORE are irrelevant
for non-users of SpamAssassin.)

in terms of figuring out which
DNSBL is in question, if it's RCVD_IN_FOO, it's generally the DNSBL
called "foo" ;)  Take a look in
http://useast.spamassassin.org/dist/rules/20_dnsbl_tests.cf for more
details.

RAZOR2_CF_RANGE_51_100 means Razor 2, with a "confidence rating" from
teh razor server of between 51 and 100.

We measure these at a point up to 6 months after the mail was received,
so that *may* mean that the BL data is no longer accurate for that mail
(e.g. if a relay is closed.)   But in practice that does not seem to be
a big issue...

What the hell, I'll just paste the ratings here:

OVERALL%   SPAM%     HAM%     S/O    RANK   SCORE  NAME
 495260   343948   151312    0.694   0.00    0.00  (all messages)
 47.918  68.8645   0.3033    0.996   1.00    1.55  RAZOR2_CF_RANGE_51_100
 54.243  77.7344   0.8459    0.989   0.99    0.90  RAZOR2_CHECK
 39.058  56.1503   0.2042    0.996   0.98    1.10  RCVD_IN_DSBL
 31.969  45.9802   0.1209    0.997   0.97    1.10  RCVD_IN_SORBS_HTTP
 27.132  39.0053   0.1441    0.996   0.96    1.10  RCVD_IN_NJABL_PROXY
 23.752  34.1549   0.1057    0.997   0.96    1.10  RCVD_IN_SORBS_MISC
 19.465  28.0124   0.0363    0.999   0.95    1.10  RCVD_IN_OSIRU_PROXY
 15.868  22.8473   0.0040    1.000   0.95    4.30  RCVD_IN_OPM
 12.937  18.6272   0.0026    1.000   0.94    4.30  RCVD_IN_OPM_HTTP
 10.065  14.4926   0.0007    1.000   0.94    4.30  RCVD_IN_OPM_HTTP_POST
  8.070  11.6201   0.0013    1.000   0.93    4.30  RCVD_IN_OPM_SOCKS
  6.901   9.9242   0.0304    0.997   0.92    1.81  DCC_CHECK
  1.104   1.5904   0.0000    1.000   0.92    4.30  RCVD_IN_OPM_WINGATE
  3.903   5.6145   0.0132    0.998   0.92    1.10  RCVD_IN_SORBS_SMTP
  0.029   0.0424   0.0000    1.000   0.92    2.80  RCVD_IN_SORBS_WEB
  0.015   0.0212   0.0000    1.000   0.92    2.80  RCVD_IN_OPM_ROUTER
  0.001   0.0015   0.0000    1.000   0.92    0.00  RCVD_IN_NJABL_MULTI
 12.520  17.9202   0.2439    0.987   0.91    1.27  RCVD_IN_SBL
  1.783   2.5591   0.0192    0.993   0.90    0.53  RCVD_IN_NJABL_DIALUP
  1.022   1.4665   0.0112    0.992   0.90    0.85  RCVD_IN_OSIRU_DIALUP
  0.359   0.0087   1.1546    0.007   0.90   -4.30  RCVD_IN_BSP_TRUSTED
  9.706  13.8724   0.2353    0.983   0.89    0.93  RCVD_IN_OSIRU_SPAMWARE
  0.082   0.0026   0.2630    0.010   0.89   -0.10  RCVD_IN_BSP_OTHER
  9.036  12.9098   0.2320    0.982   0.89    0.64  RCVD_IN_NJABL_SPAM
 41.526  58.5996   2.7169    0.956   0.88    0.10  RCVD_IN_SORBS
  3.435   4.8891   0.1302    0.974   0.85    0.00  RCVD_IN_OSIRU_RELAY
  3.143   4.4719   0.1209    0.974   0.85    2.55  RCVD_IN_DYNABLOCK
 41.161  57.6715   3.6322    0.941   0.84    0.10  RCVD_IN_NJABL
  0.361   0.5108   0.0192    0.964   0.82    2.60  RCVD_IN_SORBS_ZOMBIE
 11.074  15.4265   1.1810    0.929   0.76    0.10  RCVD_IN_RFCI
  3.185   4.4132   0.3945    0.918   0.72    1.31  RCVD_IN_NJABL_RELAY
 38.389  51.8980   7.6802    0.871   0.68    0.00  RCVD_IN_OSIRU
  3.802   5.2075   0.6060    0.896   0.67    0.00  RCVD_IN_SORBS_SPAM
  0.056   0.0718   0.0185    0.795   0.46    1.52  RCVD_IN_SORBS_SOCKS
 11.116  13.7768   5.0683    0.731   0.38    0.00  RCVD_IN_OSIRU_SPAM_SRC
  0.016   0.0180   0.0106    0.630   0.23    0.00  RCVD_IN_NJABL_CGI
  0.000   0.0000   0.0000    0.500   0.11    0.00  RCVD_IN_SORBS_BLOCK

--j.

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