Understanding Email Deliverability: SPF, DKIM, and DMARC

Why email authentication matters for your business

Why Check SPF, DKIM, and DMARC?

Email authentication is essential to prevent spam, phishing, and spoofing attacks. Ensuring proper SPF, DKIM, and DMARC records helps verify sender authenticity and improves email deliverability.

Understanding SPF

SPF (Sender Policy Framework) is an email authentication method that specifies which mail servers are permitted to send emails on behalf of your domain.

SPF records are configured in the DNS settings of your public domain. An example:

v=spf1 include:_spf.google.com ~all

A valid SPF record reduces the risk of spoofed emails being accepted by recipients, since it lists 'accepted senders'.

Understanding DMARC

DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on SPF and DKIM to specify how receiving servers should handle unauthorized emails.

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

Understanding DKIM

DKIM (DomainKeys Identified Mail) adds a digital signature to emails, allowing recipients to verify that messages haven't been altered in transit.

v=DKIM1; k=rsa; p=MIGxxx......; n=###,####,####

Proper DKIM configuration helps establish trust with email providers and prevents tampering.

Benefits of Email Authentication

Prevents email spoofing and phishing attacks
Improves email deliverability and reduces spam flagging
Protects your brand reputation
Ensures compliance with email security best practices

To explain it to a '5 year old child'

SPF record: These are the servers I will send from. If it says it's from me, but comes from somewhere else, it's likely fake.

DKIM record: This is my signature, if it's not on the email, it probably didn't come from my server.

DMARC record: If you get mail that doesn't match the above, here's what I want you to do with it.