Planet Geek

Go go gadget Greylisting!

Geekitude

Our spam levels here at Chez Geek are, shall we say, astronomical. About a year ago, we installed and configured SQLGrey, a tool for Postfix that enables Greylisting on inbound mail. Initially, it had a great impact, but somewhere along the lines, our configuration got modified in a way that stopped the greylist from working.

Last week, the spam levels got to be too much, and I checked into the greylisting configuration on our main server. It wasn't enabled! Somehow our postfix entries had gotten removed (we're guessing an overzealous edit with an RCS checkout overwriting things).

Anyway, after restarting, I've had a few days to see what impact there is. The spam dropoff has been ridiculously dramatic, as my spam reporter shows:

Breakdown by day: (10172 posts, average of 1453.1 posts per day.)
----------------------------------------------------------------------
	 Apr 20 | Apr 19 | Apr 18 | Apr 17 | Apr 16 | Apr 15 | Apr 14 
	   130  |   143  |   136  |   1393  |   3038  |   2417  |   2915

This is showing only mail that comes into my inbox, and has been tagged as spam by Amavis. This doesn't show how much mail is being rejected, but it's pretty obvious since I enabled greylisting (middle of the day on Apr 17th), things have... fallen off to something like 5% of the original level.

Now that's good stuff.

Posted by dbs at April 21, 2008 12:56 PM