We use software that allows people to clip and have coupons automatically emailed to them from our site. The coupon software sends the email for us using our email address. For example, they send the coupons using our email address "firstname.lastname@example.org"---> Our domain is "manhattanpizza.com" However they are sending the coupons from THEIR domain "pizzacoupongenerator.com" but using our email address. I believe to help with deliverability, we need to add an SPF record to our DNS that verify that pizzacoupongenerator.com is allowed to send using our email address. Specifically what record would we want to add? Thank you for the help, let me know if I can help clarify the issue if I have not explained it clearly.
If I am not mistaken your customer needs to add a SPF record in their DNS as such.
IP address/system name your emails are coming from? ie: smtp.manhattanpizza.com
"v=spf1 a:smtp.manhattanpizza.com ~all"
What this does is tells receiving email servers that your customers domain approves emails being sent from smtp.manhattanpizza.com
Hope this helps.