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 "email@example.com"---> 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.
Some people will not recieve the email without an spf record. You are correct, the best way is to add any domain the emails appear to come from. If you run your own server and have WHM then you will need to enable SPF for each cpanel account that needs it. Then in cpanel under Email Authentication enable SPF and then add a record in "Include List (INCLUDE):"