Steven Stern wrote: > If you can get away with the delay, greylisting does an amazing job. I get > almost no spams with it enabled. Unfortunately, even though it's sent to > request a retry after 30 seconds from the sender, some senders can take up to > three hours before retrying.
At SMTP time there is no request to retry after 30 seconds. It is either an accept, a soft failure or a hard failure. Those are the options. The SMTP sender has no knowledge of your greylisting and so won't know if it would succeed after 30 seconds, an hour or five days. Sending SMTP daemons retry on their own schedule. Usually that is every 30 minutes. But some very busy sites will put the mail in a deferred queue where it might sit for much longer. And of course there are the just plain misconfigured sites and plain broken software. But generally greylisting works well. Bob
