IPv6 mail The Reg does 240/4

Sat Feb 17 22:21:32 UTC 2024

It appears that Michael Thomas <mike at mtcc.com> said:
>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.

It definitely does, since there are plenty of IPs that send only
malicious mail, or that shouldn't be sending mail at all. Every large
mail system uses Spamhaus' IP lists as part of their filtering
process. 

I hear that SPF is largely useless these days because most SPF records
include IP ranges for many mail providers, and a lot of those
providers do a poor job of keeping one customer from spoofing mail
from another. DKIM is still quite useful.

K. 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.

Unfortunately, spammers can read just as well as we can so it's not
going to happen.

R's,
John