Wed, 01 Nov 2006
Spam, spam, spam
It seems that the total volume of spam has increased radically during the last month. My own spambox is bigger than before - the previous spambox had 770MB and 56k messages, the current one has over a gigabyte and 71k messages (we rotate spamboxes on 10th each month, so the current one will probably be about 50% bigger than it is now). So it would be an increase in spam almost by factor of two in the last month. I am getting more than 3500 spam messages a day, one spam each 24 seconds! And this is just spam recognized by my spam filter, I guess 20-50 messages get through each day.
The IS MU mailserver could not cope with this volume of spam, and the CPU load has caused huge delays in message delivery. So, as a temporary measure, I have switched off some spam filtering features (causing a big uproar amongst users), and I have started to reimplement the server part of the mailserver.
I have replaced Qmail with Postfix (expect more about life with Postfix in the next blogspot :-), added PostGrey, and rewrote the delivery mechanism so that entire our cluster is used for spam filtering (instead of the mailserver only). I have also added ClamAV antivirus scanner.
So, the current IS MU mailserver should be an order of magnitude faster than before, and it will be even more spam-resistant because of additional antispam measures such as greylisting. It took me about three weeks to redesign and reimplement it, but I think we are prepared for the next wave of spam.
Footnote : Of course, when somebody complains "Fix your f*cking spam filter, I receive five spams a day!", I can always reply "Lucky you, I get 3500+ spams daily." :-)