On 21 May 2020, at 12:49, Charles Sprickman wrote: > I was wondering if greylisting might be a good option here. It's a matter of how much Nanking you are willing to do and how much = legitimate mail your are willing to lose. The usual method of greylisting where you tell a server to try again = later (4xx error) will cost you legitimate mail as many senders, = including very large senders, will retry from different servers (google, = Amazon). Others, in the idiotic belief they are being "secure", will = never retry. Many of the latter are banks. Other forms off greylisting, like slowing the connection rate and making = the transaction take a bit longer than usual are far more effective and = less likely to cause issues with legitimate senders. Greylosting also really screws up the "authenticate your email right = now. No, right this second. We sent you the code, enter it now in the = next ten seconds or we delete your account and ban your IP" idiocy on = the web that, nonetheless, some of us are forced to deal with. It's = impossible to keep up with the list of domains doing that, especially = when most of the verification emails originate from other servers. Postscreen, out-of-the-box, works exceptionally well and blocks more = spam than any thing else I've used. Sure, I run SpamAssassin as well, = but it sees very little use. Add an RBL or two, and it's kind of like magic. --=20 Knowledge equals power... --... Power equals energy... People were stupid, sometimes. They thought the Library was a dangerous = place because of all the magical books, which was true enough, but = what made it really one of the most dangerous places there could ever be was the simple fact that it was a library. Energy equals matter... --... Matter equals mass. And mass distorts space. It distorts it into polyfractal L-Space. --Guards! Guards!