Weekly spam summary on January 7th, 2006

January 8, 2006

It's time for the first weekly spam summary of the new year, so let's see what sort of a start 2006 is off to.

This week we received 14,639 email messages from 198 different IP addresses. Our SMTP server handled 30,023 sessions from 3,122 different IP addresses. Message volume is up some since last week (not surprising with people coming back to work) and session volume is holding steady.

Connection volume is down from last week: 201,000 connections from at least 58,500 different IP addresses, although with a highwater of 20 connections being checked at once. By day we get:

Day Connections different IPs
Sunday 28,000 +8,400
Monday 32,000 +11,060
Tuesday 30,650 +10,530
Wednesday 29,480 +7,860
Thursday 35,980 +7,530
Friday 22,540 +6,990
Saturday 22,190 +6,130

I have no explanation for the day to day numbers, although we do have the traditional Thursday jump. It's wierd to see the different IP address count spike so sharply without a connection spike to go with it.

Kernel level packet filtering top ten:

Host/Mask           Packets   Bytes         17983   1079K        12414    745K         10004    509K           9387    411K            8249    396K          6840    356K          6579    335K           6449    297K        5956    275K        5454    251K
  • only reappears from before, still without a good IP to name mapping.
  • is also without good IP to name mapping.
  •,, and are all considered 'dialup' dynamic address machines.
  • is a PacBell DSL machine that kept trying to send us mail from an address that had hit our spamtraps.
  •,, and had unresolvable HELO names.

Connection time rejection stats:

  36555 total
  18969 dynamic IP
  10916 bad or no reverse DNS
   4114 class bl-cbl
    528 class bl-spews
    467 class bl-sbl
    310 class bl-dsbl
    272 class bl-sdul
     52 class bl-ordb
     30 class bl-njabl
     14 class bl-opm

Given the overall volume drop from last week, I think that these stats are not particularly surprising. There are no really aggressive single IP addresses, and the CBL doesn't stand out as much as it did last week; only 7 of the top 30 most connecting IP addresses are on it.

what # this week (distinct IPs) # last week (distinct IPs)
Bad HELOs 8120 406 12700 578
Bad bounces 4349 1629 4196 1123

It looks like we're still getting forged as the MAIL FROM origin by spammers.

The Hotmail spammers seem to have ended their holidays too, judging from the Hotmail stats for this week:

  • 2 emails accepted, one of which was a backscatter bounce.
  • 275 messages rejected because they came from non-Hotmail email addresses.
  • 62 messages sent to our spamtraps.
  • 4 messages refused because their sender addresses had already hit our spamtraps.
  • 5 messages refused due to their origin IP address (four for being in the SBL, one for being in the CBL).

This is broadly consistent with the volume from the week before last. So much for any hope that Hotmail was doing something to deal with their spam problem over the Christmas to New Years break.

(In fact they were doing something last week: they were making it more difficult to report spam to Hotmail. Now you have to use report_spam@hotmail.com instead of abuse@hotmail.com if you want them to take any action, or so their autoreply now says.)

Written on 08 January 2006.
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Last modified: Sun Jan 8 02:24:09 2006
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