This question already has an answer here:
How can a mail server send authenticated mail (using DKIM, SenderID, SPF etc) without adding records to the sending domain name's DNS server?
I've read Jeff Atwood's very useful guide to sending mail so it doesn't end up in spam. I've also read many other articles on the topic, but they all need modification of sending domain name's DNS server.
I'd like to create these records on my mail service's domain name, but authenticate mail from other domain names. MailChimp does this, where you can send mail from any email address (after email verification), but don't need to edit DNS records.
There's this answer which refers to MailChimp setting the
Reply-to: header and sending
From: a MailChimp email address, but I've checked some campaigns sent to me, and the
From: is not a MailChimp address, but the sender's address.
EDIT: Here's a paste of the headers from a MailChimp campaign as seen in Gmail
Can anyone shed some light on how this is done?