All you need to know about cross-domain anti-spoofing prevention in Exchange Online

More of a whitepaper than an article, the following describes in detail what cross-domain spoofing is and what you can do to protect yourself against it: https://support.office.com/en-us/article/anti-spoofing-protection-in-office-365-d24bb387-c65d-486e-93e7-06a4f1a436c0?ui=en-US&rs=en-US&ad=US

 

It's a long read, but definitely worth it, as it gives you tons of insights, as well as information on what's coming in the future.