The Reg does 240/4

Sat Feb 17 19:01:48 UTC 2024

On 2/17/24 10:19 AM, Owen DeLong via NANOG wrote:
> Mike, it’s true that Google used to be a lot less strict on IPv4 email 
> than IPv6, but they want SPF and /or DKIM on everything now, so it’s 
> mostly the same. There is less reputation data available for IPv6 and 
> server reputation is a harder problem in IPv6, but reputation systems 
> are becoming less relevant.

I kind of get the impression that once you get to aggregates at the 
domain level like DKIM or SPF, addresses as a reputation vehicle don't 
much figure into decision making. But what happens under the hood at 
major mailbox providers is maddeningly opaque so who really knows? It 
would be nice if MAAWG published a best practices or something like that 
to outline what is actually happening in live deployments.

Mike