Re: offtopic: rant about thoughtless enabling DMARC checks [was: Re: Bounces?]

[Aki Tuomi via dovecot]

On 09 February 2019 at 20:48 Juri Haberland via dovecot < dovecot@dovecot.org> wrote:

On 09/02/2019 10:44, Aki Tuomi via dovecot wrote:

For some reason mailman failed to "munge from" for senders with dmarc policy ;(

It's now configured to always munge to avoid this again.

I'd say, let Mailman throw all people off the list that have enabled DMARC

checking without using exceptions for the lists they are on. It's a known

fact that DMARC does not cope well with mailing lists. Blindly enabling

DMARC checks without thinking about the consequences for themselves should

not be the problem of other well behaving participants.

The problem is that it would drop all gmail users for a start, which there are plenty of. Also judging from the amount of bounces ww got it seemed like half the subscribers would drop out.

Most people use OpenDMARC and there are patches to mark certain hosts as

mailing lists senders, so it is possible.

Wonder how many would do this though?

And everyone using p=reject should think about it as well - as I said,

DMARC does not play well with mailing lists, so setting p=reject on a

domain used to participate on mailing lists is not wise, to say the least.

You should not follow Yahoo and AOL - you know, why they did it, don't you?

Unfortunately this is usually required by many common providers such as microsoft and google, otherwise they refuse your mail.

And Aki, please go back to "munge only if needed" - munging all messages

leads to a really bad "user experience".

It does not seem to work correctly. I'll review the settings when we manage to upgrade to mailman3

Thanks.

Hope you understand .

Aki

Back to lurking,

Juri

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Aki Tuomi