On Mon, 13 Mar 2017, Carsten Bormann wrote:
The most likely outcome is that local admins will “upgrade" our mail system by turning off IPv6. (We have had IPv6 deployed for some 18 years now.)
On Mon, 13 Mar 2017, Philip Homburg wrote:
Getting mail delivered to gmail over IPv6 works most of the time without ever setting up SPF or DKIM. Gmail does seem to be the single most unreliable mail server that I know of, mostly due to their attempts to be more strict on IPv6.
As I hope everyone knows, receiving mail requires orders of magnitude more work than sending it. Even 20 years ago before spam was an issue, recipients had to receive it, route it, store it somewhere, filter it with sieve or procmail, and provide POP or IMAP for the recipient to collect it. These days, with 90% of mail being spam or worse, there's another magnitude of work in trying to separate the real mail from the flood of junk. Or try this thought experiment: how hard would it be to send a million messages a day from your laptop (easy), and how hard would be be to receive and deliver a million messages a day on that laptop (impossible.)
The point of authentication schemes like SPF and DKIM is to make it easier for recipients to tell that your mail is from you, so they can treat it differently from the spam. Everywhere else, the response is OK, I would prefer that people get the mail I send them, I will set up authentication because it is not hard (SPF takes about 5 minutes), and it helps the people who are handling my mail with the mail system they are paying for.
I can also assure you from many conversations with large mail providers that you will increasingly find that recipients will conclude that if you can't be bothered to authenticate your mail, they can't be bothered to deliver it. It's their mail system, they get to do that.
In the IETF, for some reason, people take a perverse pride in offering no help whatsoever to mail recipients, even when that help costs them nothing, and then snark and whine when the recipients have trouble dealing with the unauthenticated mail. I don't understand why, but I really wish people would stop. Nobody is impressed that your mail system does exactly what it did 20 years ago, and it gives outsiders the impression that the IETF is a bunch of out of touch sociopaths.
R's, Johh