DMARC, DKIM, SPF & BIMI: 5-minute playbook for Security and Marketing

TL;DR:

• SPF: Authorizes which servers can send your email
• DKIM: Cryptographically signs emails to prevent tampering
• DMARC: Enforces authentication and tells servers what to do with failures
• BIMI: Displays your verified logo in inboxes (requires DMARC enforcement)

Why it matters: Email authentication stops impersonation attacks while improving deliverability and adding visual branding to your emails.

The playbook: Implement SPF/DKIM → Deploy DMARC monitoring → Move to enforcement → Add BIMI for logo display.

Bottom line: Security gets protection, marketing gets better engagement, customers get safer inboxes. Win-win-win.

If your brand sends email, you’re in the authentication business. Domain-based Message Authentication, Reporting, and Conformance (DMARC), DomainKeys Indentified Mail (DKIM,) Sender Policy Framework (SPF), and Brand Indicators for Message Indenfitication (BIMI) are now table stakes for deliverability, phishing defense, and brand trust — especially as inbox providers liek Google, Yahoo and Microsoft tighten sender rules and raise the bar on compliance.

• SPF: Lists authorized sending sources for your domain (DNS record).
• DKIM: Cryptographically signs mail so receivers can verify it wasn’t altered.
• DMARC: Aligns SPF/DKIM with “From:” and tells receivers what to do with failures (none/quarantine/reject). Also unlocks reporting so you can see who’s sending on your behalf.
• BIMI: Shows your verified logo in the inbox once DMARC is enforced and logo requirements are met (VMC/CMC).

1. Inventory senders (marketing platforms, CRMs, gateways).
2. Fix SPF & DKIM alignment for each sender.
3. Publish a DMARC record at p=none, collect/triage reports.
4. Tighten policies (move to quarantine, then reject) once legitimate traffic is aligned.
5. Enable MTA-STS & TLS-RPT to protect SMTP in transit and get visibility into transport issues.
6. Add BIMI once DMARC is at enforcement for brand lift and trust signals.

Teams using Red Sift OnDMARC typically reach enforcement in 6–8 weeks, helped by guided workflows and instant troubleshooting (no need to wait for daily reports).

• CISOs & Security Leaders: Reduce domain spoofing/BEC risk and prove control with clear reporting.
• Security Engineers/Managers: Cut time-to-fix with real-time checks, sender discovery, and automated records.
• VP & Heads of Marketing: Protect deliverability and leverage BIMI to boost recognition, stand out in the inbox and increase open rates.

Expired or misconfigured TLS/PKI can torpedo deliverability and trust. Add free certificate monitoring to prevent outages and compliance gaps, and roll out MTA-STS/TLS-RPT to harden mail transport.

• Run a free readiness check with Red Sift Investigate (SPF/DKIM/DMARC/BIMI in under a minute).
• Accelerate to enforcement with OnDMARC and then add BIMI.
• Turn on free certificate monitoring to catch expirations before they bite.