What is DMARC?

In this article:

DMARC, which stands for “Domain-based Message Authentication, Reporting & Conformance”, is an email authentication, policy, and reporting protocol. DMARC helps make it easier for email senders and receivers to determine whether an email is legitimate and what to do if isn't. This assists in identifying spam and phishing messages and prevents them from landing in people's inboxes. Information is gathered from senders and receivers using DMARC and helps improve the mail authentication infrastructure so that all their mail can be authenticated. It also gives the legitimate owner of an Internet domain a way to request that illegitimate messages – spoofed spam, phishing – be put directly in the spam folder or rejected outright.

For more information please visit: https://dmarc.org/wiki/FAQ#Why_is_DMARC_important.3F 

For information on how to add DMARC to your TierraNet account: How to add a DMARC record to your domain