I've not set this up, but I'm sure you don't need to add the SPF to include all the servers of all the people in the mailing list.
The SPF/DMARC only apply to the actual server that sends the email to the group, not the person who sends the email into the server.
What I mean is:
Group member emails your group email mygroup@mydomain.com from groupmember@example.com - the SPF and DMARC of this email is checked by the mail server on mydomain.com to check it matches with the allowed senders for example.com.
The group management software on mydomain.com then sends the email out to everyone in your group. This email might have an apparent 'from' address of the original sender, but if you look in the headers you'll see it actually comes from something like mygroup@mydomain.com
Hence, the receiving servers check the SPF and DMARC to ensure that the server is one of the allowed senders for mydomain.com - not the domain of the person who sent the email to the list.
So - to cut a long story short: You really only need the SPF and DMARC rules for your own domain and email server in your domain's DNS records. Don't worry about all the servers of all your members!
And as you say - e-voice doesn't do any email hosting or mailing lists. But we do like to help wherever we can!
Thanks
Joe
It does seem very odd and was guided by this article..
https://www.cloudflare.com/learning/dns/dns-records/dns-spf-record/
but since adding the TXT SPF record I am not receiving the email bouncebacks (yet!).
Can I send you one of the bounce messages that I get to see if it makes any sense. (It is too long to add to the forum post.,)
I can't stop you sending it, but I probably won't look at it! But for good reason...
When I was setting up the SPF and DMARC for e-voice I found https://www.mail-tester.com/ to be very helpful. You send an email to their service and it tests that all the settings are correct.
You can keep testing until it's all sorted, and it appears to be free.
Thanks
Joe