[ios84dev]

Why are graylists that horrible? All it does is require the sending server to retry 5 minutes later; I don't see how that would have any impact on a business unless they are in the habit of being on the phone with new customers and asking them to send an email at the same time.

[danielweber]

Assuming the sending server does that. Maybe it takes a few hours. Maybe it doesn't. Small businesses can be a mess, and you can't say "well, your customers suck" when the client complains about how greylisting is working for him.

[bigiain]

I've seen many poorly written web form handlers that try to do SMTP themselves, and that clearly don't ever attempt to retry graylisted failures...