Email authentication is the general term for technology that allows a mail server to determine if a given inbound email message is authentic or not. In other words, it allows a mail server to determine if a message that appears to be from "firstname.lastname@example.org" really is from Yahoo, or if it was forged or spoofed (i.e. spam). Senders use email authentication to help improve the deliverability of their emails and ISPs use email authentication to help prevent spam.
Email authentication technologies can be an alphabet soup, but the primary technologies used across the Internet today include:
- SPF (Sender Policy Framework)
- Sender ID
- DKIM (DomainKeys Identified Mail)
- DMARC (Domain-based Message Authentication, Reporting, & Conformance)
In general, Direct Mail handles all of these authentication technologies for you when you send via e3 Delivery Service. If you send via your own server, you'll need to configure your email server to support these technologies.
If you are interested in signing with your own DKIM key or adding our SPF/SenderID records to your domain, please see this help article for more information.