Friday on the NPR radio program Geek Speak, from KUSP Santa Cruz, CA, the subject was on a 2 year old white papered technique called ‘grey listing’. It sounds wonderful when used alongside a real time blacklist.
It works like this: If an SMTP server comes knocking, and has never visited before, it gets rejected with a minor timeout error code. That keeps away the spambots, simple as that. Real servers will always try again.
There’s more detail on the archived radio show:
Now before you go thinking a simple spam server software upgrade will even out the arms race again, here’s how it works with a black list:
Spam SMTP knocks, gets sent away. In the meantime the real time black list gets notified of it’s activity and added to the list. Next time it comes knocking, Domino sees it’s round two PLUS it’s on the blacklist, IP gets blocked.
The original paper is here:
http://projects.puremagic.com/greylisting/
Here’s another related site:
As soon as I heard this, I did a search on notes.net to see if it had previously been discussed. It was here:
…but rather inconclusively. After hearing the radio discussion with the paper’s author, it seems like a realistic thing to do with Domino. In fact, it’s a wonder why more mainstream mail ISPs don’t tout it at all. The geeks on the radio said they simply installed a Debian package on their mail server and spam dropped to zero.
What do you folks think? If such a solution is ‘project-size’, perhaps I should suggest this as an OpenNTF idea. On the surface, it seems fairly easy to tweak Domino this way.