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I am familiar with the basics of SPF but I am having trouble determining exactly what I need for my setup.
I have my email done through Google Apps to send and receive email for my domain, example.com. Now I am adding Mailchimp Mandrill as a valid outgoing SMTP server for the same domain. I currently dont have an SPF record set up for Gmail.
When creating the SPF record for spf.mandrillapp.com, do I need to include gmail.com also? Or example.com? Or all three? Or only Mandrill?