* Mike Hillyer via mailop: > I've seen people drop it to a minute when they know they are being > greylisted and be fine, but it's certainly something to do while > watching closely.
Yep, keeping a watchful eye is a good idea. The issue with greylisting is that it takes two to dance. Lowering the time between delivery attempts on the sender's side does not reduce delivery time unless the receiving server plays along — which the sender can't control. While Rspamd, to name just one example, currently has a default greylisting timeout of 5 minutes [1], the value may be different based on admin choices. [1] https://docs.rspamd.com/modules/greylisting/ Other greylisting mechanisms are also available, of course. What their timeouts are, and how these mechanisms react to senders repeatedly knocking on their door during their greylisting period (ignore, treat as attacks, etc.), is typically unknown to the sender. Attempts on the sender side to figure out the "best" retry timing for individual recipients may therefore require a lot of experimentation, or even backfire by way of temporary blocks. Oh, and greylisting timeouts may vary with server load, just to make things harder. I would not invest much effort into fiddling with retry/backoff timings in Postfix. A greylisting problem on the receiving end cannot be fixed in this way, I think. If confirmation codes/tokens only have a 10 minute lifespan, email is not the correct choice of transport. -Ralph _______________________________________________ mailop mailing list -- [email protected] To unsubscribe send an email to [email protected]
