On Mon, Aug 27, 2007 at 04:22:08PM -0400, Don Dailey wrote: > > On Mon, 2007-08-27 at 21:35 +0200, Heikki Levanto wrote: > > Some mail servers are starting to use greylisting, which > > intentionally delays mails that have sender-recipient pairs they > > have not seen before - this fouls a lot of spamming programs (I do > > that at my place of work). > > How does this foul spamming programs? Does it prevent a spammer from > sending out a lot of email or just delay the receiving of it?
Many spam programs are not fully capable mail programs, and have not implemented any sort of retry mechanism. I was sceptical about it too, until I installed it. Perhaps the spammers are catching up now, but a year ago, it dropped more than 75% of incoming spam - enough that our mail server could afford to do proper filtering on the rest. And it is not like all mail gets delayed, the filter keeps a hash of sender-address, receiver-address, and connecting IP-address. If it has accepted one mail with a matching hash in the past 45 days, no delays are imposed. But this is getting off topic. - Heikki -- Heikki Levanto "In Murphy We Turst" heikki (at) lsd (dot) dk _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
