How to Fix a Missing DMARC Record (Plain-English Guide for Omaha Businesses)

If you ran our Website Vulnerability Scanner and got flagged for a missing DMARC record, you're in good company — a large share of the Omaha small business websites we scan are missing DMARC entirely. The fix takes 15 minutes and you don't need a developer. Here's exactly what to do.

What Is DMARC and Why Does It Matter?

DMARC stands for Domain-based Message Authentication, Reporting & Conformance. In plain English: it's a small text record in your domain's DNS that tells the world's email servers what to do with messages claiming to come from your domain.

Without DMARC, here's what an attacker can do in five minutes:

• Send an email from billing@yourcompany.com to one of your customers
• Attach a fake invoice with their bank account number
• Have it delivered straight to the inbox — because nothing is checking whether they're authorized to send as you

This is called a spoofing attack, and business email compromise is consistently one of the costliest forms of fraud reported to the FBI's Internet Crime Complaint Center (IC3), with small businesses regularly losing five- and six-figure sums to spoofed wire-transfer emails.

How DMARC Stops It

When you publish a DMARC record, you're telling Gmail, Outlook, Yahoo, and every other major email provider three things:

1. Here are the servers authorized to send mail as my domain (via SPF and DKIM)
2. Here's what to do if someone tries to send mail that fails those checks (reject it, quarantine it, or just monitor)
3. Send me reports about who's trying to spoof my domain

Once DMARC is enforced (p=reject), spoofed emails get rejected before they hit anyone's inbox.

The 15-Minute Fix (Step by Step)

Step 1: Confirm SPF Is in Place First

DMARC depends on SPF and DKIM. Most businesses already have SPF — it's the record that says "Google/Microsoft 365 sends mail for me." If you use Microsoft 365, your SPF should look like:

v=spf1 include:spf.protection.outlook.com -all

If you use Google Workspace:

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

If you don't have SPF, fix that first — your scanner report will flag it.

Step 2: Log Into Your DNS Provider

This is wherever you manage your domain — GoDaddy, Cloudflare, Namecheap, Google Domains, AWS Route 53, etc. Look for "DNS records" or "DNS management."

Step 3: Add a TXT Record

Create a new TXT record with these values:

• Name / Host: _dmarc (some providers want _dmarc.yourdomain.com — check their docs)
• Type: TXT
• Value: v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com; pct=100;

Replace dmarc-reports@yourdomain.com with a real mailbox you check (or use a free service like Postmark DMARC Digests or Valimail to aggregate the reports for you).

Step 4: Wait 24–48 Hours, Then Re-Scan

DNS changes take time to propagate. Re-run the Vulnerability Scanner in a day or two — your DMARC finding should be gone.

Why You Started With p=none (and What's Next)

The policy p=none is monitor-only mode. It doesn't reject anything yet — it just collects reports. This is intentional: you want to see WHO is currently sending email as your domain before you start blocking. You'll usually find:

• Your CRM (HubSpot, Salesforce)
• Your email marketing tool (Mailchimp, Constant Contact)
• Your payroll provider (Gusto, ADP)
• Maybe your accounting software (QuickBooks Online)

Each of these needs to be added to your SPF record OR have DKIM set up. Once you've reviewed 30–60 days of DMARC reports and confirmed all legitimate senders are authorized, escalate to:

v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@yourdomain.com; pct=100;

And eventually:

v=DMARC1; p=reject; rua=mailto:dmarc-reports@yourdomain.com; pct=100;

That's the gold standard — full enforcement, so mail that fails authentication for your exact domain gets rejected (lookalike domains still need separate monitoring).

Common Mistakes to Avoid

• Don't skip the monitoring phase. If you go straight to p=reject, you'll start bouncing legitimate emails (your CRM, your invoicing tool) and not know it for weeks.
• Don't forget about subdomains. Add sp=reject to your DMARC record once you're enforcing — otherwise marketing.yourdomain.com is still wide open.
• Don't use a fake email for rua. Reports are useless if no one reads them.

Need Help?

If this all sounds like a lot, it doesn't have to be your problem. DME Computer Services handles DMARC setup and monitoring as part of every cybersecurity engagement. How fast you reach full enforcement depends on how many systems send mail as your domain — the monitoring phase alone usually runs 30–60 days before it's safe to enforce. Call 402-650-8407 or request a free 30-minute walkthrough.

Related reading:

• What Is HSTS and Why It Matters
• Content Security Policy in 10 Minutes
• Run a free vulnerability scan on your website