On 4/8/2011 10:57 PM, Stan Hoeppner wrote:
email builder put forth on 4/8/2011 10:14 PM:
Or is this merely a poor-man's greylisting?
In essence, yes.
No, not at all.
Greylisting breaks the connection and forces the client to
reconnect after a cool-down period before accepting mail.
Greylisting has been quite effective against spambots, but at
the price of delaying mail from legit clients. Just about all
greylist implementations have some sort of auto-whitelist
function to not penalize proven good clients.
The sleep restrictoin only delays postfix responses, does not
break the connection, and even when first invented was not
particularly effective against bots. I expect it's even less
effective now, but I don't know anyone that's tried it lately.
-- Noel Jones
