Forrest Christian (List Account) wrote:

I've been ignoring this discussion because I feel this ship sailed many years ago, and IPv6, like it or hate it, is the best way
forward we have.

A problem is that there is a cliff edge in front of you.

Likewise for spam filtering - spam filtering would be knocked back to the stone ages if IPv4 disappeared overnight. IPv6 is a spam sender's dream come true, since IPv6 DNSBLs are practically worthless. Yes, there are OTHER filtering techniques, but none that scale nearly so much with as extremely little resources required. And this is a problem for large and small organizations. Even the very largest email systems would be extremely disrupted if IPv4 DNSBLs (internal and/or 3rd party) were not available within the very near future. Solutions to this problem would then severely disrupt their business/financial models for those mail systems since the overhead costs per mailbox would significantly increase.

-- 
Rob McEwen
https://www.invaluement.com