For the last week or so I've been experimenting with a new, for me (actually the concept itself is only a couple years old), anti-spam measure called greylisting. The basic idea takes advantage of the fact that most spamming software doesn't retry when a message is temporarily delayed. So if you make all mail wait a while, and make a record of whether they already tried, you cut out most spam. You also keep a record of what sender/receiver pairs have already successfully undergone the process, and you don't delay them for future messages.
Well it turns out that it seems to work really really well. There's some kinks to iron out, but the fact is that it cuts down on 95% of spam. Some of my users are reporting various problems, but I think I'm working them out. It's really almost eerie how well it works, because the total volume of email is just so much lower coming into my email box. As far as I can tell I'm not missing anything, but it feels like I might be, because there's so little email -but that's because most of my email was spam before. Which, as a user pointed out, is sad, isn't it? I'm sure it's true of everyone these days.
Posted by steev at Enero 19, 2005 08:46 AM