On Tue, Jan 12, 2010 at 11:11:13AM -0800, Michael Thomas wrote:
Blocking generic and residential addresses is the single most effective thing we've ever done to reduce spam.
Really? You mean that if you stopped doing this you'd have trillions, or quadrillions of spams per day instead now? I'm skeptical.
The original statement is accurate, and becomes nearly an absolute if qualified with the addition of "...from zombies". This is common knowledge among everyone with sufficient $clue in the field, and has been for most of the past decade. Remaining research/discussion/debate is now focused on how best to enumerate such space, either by PTR or by allocation. Given that the zombie population continues to monotonically increase with no sign that the trend will reverse, and given that precious few owner/operators of such space have taken appropriate, timely and effective actions to staunch the flow of outbound abuse from the zombies within their operations, it seems reasonable that this tactic will remain extremely useful into the forseeable future. Once again, I direct those interested to the spam-l list (and its archives) where copious discussion on these points may be found, and is much more on-topic than here on NANOG. ---Rsk