Kevin A. McGrail wrote: > This is a good point that you aren't bouncing the email for this, just > tempfailing for grey listing purposes. I wonder for how much longer > greylisting will be effective though. I figure ratware will eventually have > to figure it out, no?
Greylisting will continue to be effective for the following reasons: 1) If ratware does *not* adapt to greylisting, then obviously greylisting will continue to work. 2) If ratware *does* adapt to greylisting, then the sender of a given spam will be "pinned" to a given IP address for some minutes or hours, thereby giving DNS-based RBLs more time to catch up. Both prongs of this pincer movement are necessary for greylisting to really work well. "But," you object, "if everyone uses greylisting then submissions to DNS-based RBLs will likewise be delayed and we're back to square one!" The answers are that (a) honeypot systems won't use greylisting, and (b) if you greylist after the final "." (as our commercial products do), you can still run automated analyses of message content and report obvious spam to DNS-based RBLs. (We greylist after "." so as not to break certain nameless substandard commercial SMTP implementations. No, M$ Exchange is *not* guilty in this case!) Regards, David. _______________________________________________ NOTE: If there is a disclaimer or other legal boilerplate in the above message, it is NULL AND VOID. You may ignore it. Visit http://www.mimedefang.org and http://www.roaringpenguin.com MIMEDefang mailing list [email protected] http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
