Re: is it just me or...

["John R. Levine via NANOG" <nanog () lists nanog org>]

On Mon, 26 May 2025, Randy Bush wrote:
> but back to technology.  of the myriad of protection techniques in use
> by providers large and small, statistically which reject/protect-against
> how much?  actual measures.  ip-range filtering, smtp protocol errors
> & violations, et alia vs dkim, dmarc, even spf.

No two mail systems are the same, and large mail systems don't publish 
their stats because they don't want to give more hints to the crooks. 
Small mail systems vary so much that even if you tried to collect and 
combine stats, it's unlikely it would tell you anything more than that 
mail systems vary a lot and we already know that.

It doesn't make much sense to try to ask about individual techniques 
because they are invariably used in combination in scoring systems, and 
they have told me informally that there are often combinations that you 
wouldn't a priori expect to be useful that are, and vice versa.

R's,
John
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