Weekly spam summary on April 22nd, 2006

April 23, 2006

This week's statistics are atypical, because in pursuit of better CBL statistics I moved our CBL check before all of our other connection time checks (including our greylisting) and pretty much stopped adding IP addresses to our kernel filters during the week.

Bearing that in mind, this week we:

  • got 12,845 messages from 226 different IP addresses.
  • handled 17,723 sessions from 788 different IP addresses.
  • received 141,631 connections from at least 38,000 or so different IP addresses.
  • hit a highwater of 50 connections being checked at once, hit today (this Saturday).

This is all up from last week, but not too much. The per day table is more or less flat, with a peak of 28,000 connections this Monday.

Kernel level packet filtering top ten:

Host/Mask           Packets   Bytes         8967    456K       5903    294K        5015    254K          3436    165K         3365    162K          3293    165K           2011    101K         1861   93084         1801   88876           1722    103K

Here we see the effects of pretty much not adding anything to the kernel filters all week. This leaves very few active individual IP addresses:

  • hit spamtraps (although not early enough to save some of our users) and then kept mailing and mailing.
  • and are Korean IP addresses without working reverse DNS.
  • reappears from last week, still trying to send phish spam email.
  • is a centrum.cz mail machine.

Connection time rejection stats:

  79352 total
  58949 class bl-cbl
   8680 dynamic IP
   8007 bad or no reverse DNS
   2071 class bl-ordb
    466 class bl-njabl
    429 class bl-dsbl
     67 class bl-sdul
     39 class bl-sbl
     30 class bl-spews
      8 class bl-opm

Yes, you read that right; 75% of our rejections were due to CBL listings. This isn't too surprising; the last time I looked at the stats (although over a shorter period) it was actually higher. The popularity of the ORDB is probably because of not putting heavy rejection sources into the kernel filters; just four IP addresses accounted for 80% of the ORDB rejections.

This week was obviously the week of really active connection time rejection sources, since practically none of them got put into the kernel filters. Here's a little table of the top ten:

Count IP Why
872 dialup
720 dialup
599 baddns
599 bl-ordb
570 baddns
501 bl-ordb
499 bl-cbl
366 bl-ordb
352 bl-cbl
352 baddns

(The fourth ORDB IP address is, with 189 rejections; it's down at #24 on the top 30 most rejected IP addresses.)

The Hotmail stats are up a bit this week:

  • 3 messages accepted.
  • 1 message rejected because it came from non-Hotmail email address (from hotmail.fr; possibly I should fix that).
  • 7 messages sent to our spamtraps.
  • no messages refused because their sender addresses had already hit our spamtraps.
  • 3 messages refused due to their origin IP address (two from SBL37487 (oh look, our old friends Gilat-Satcom), and one from Ghana).

The final set of numbers:

what # this week (distinct IPs) # last week (distinct IPs)
Bad HELOs 953 44 709 63
Bad bounces 21 16 70 53

Bad bounces have dropped like a stone, although I'm not going to hold my breath hoping that they stay there. The count of bad HELOs is up a bit, but that's not surprising because I didn't throw prolific sources into the kernel level blocks this week like I usually do.

This week's really prolific bad HELOs: (184 times), (145 times), (138 times), and (96 times). By contrast, last week the most prolific source only had 67 rejections.

Written on 23 April 2006.
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Last modified: Sun Apr 23 01:27:44 2006
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