Until recently, not much could be done to prevent Email Crimes. But then the DMARC standard was created and suddenly your domains are much safer.
Google, Yahoo, AOL and a group of other large email senders and receivers banded together in 2012 to develop a new framework for sending and receiving email that is designed to stop phishing attacks and other email-borne scams.
DMARC, which stands for “Domain-based Message Authentication, Reporting & Conformance”, is an email authentication protocol. It builds on the widely deployed SPF and DKIM protocols, adding a reporting function that allows senders and receivers to improve and monitor protection of the domain from fraudulent email.