Oklahoma COIT talk on email auth protocols: spf,dkim, and dmarc.
Link to slides: https://docs.google.com/presentation/d/1hhd0AaPF7uBNd0t_F-JX6y7zKDDP6DD_MS-HMv86ywo/edit?usp=sharing
How to create your DMARC record in 15 Min: https://blog.returnpath.com/build-your-dmarc-record-in-15-minutes-v2/