🚨 Facing DMARC Issues? Let’s Fix Them!
DMARC (Domain-based Message Authentication, Reporting, and Conformance) is a powerful tool to prevent email spoofing and phishing. But when it doesn’t work as expected, troubleshooting can be frustrating. Whether emails are still failing authentication or reports aren’t showing expected results, this guide will help you debug your DMARC setup step by step.
🔍 Step 1: Verify Your DMARC Record
Before diving deep, let’s ensure your DMARC record is correctly published.
✅ Quick Check:
Run this command in your terminal:
nslookup -type=TXT _dmarc.yourdomain.com
You should see a TXT record like this:
v=DMARC1; p=reject; rua=mailto:[email protected]; ruf=mailto:[email protected]; fo=1
Common Issues:
No record found? Ensure your DMARC record is published in your domain’s DNS settings.
Syntax errors? Use online DMARC checkers to validate the record.
Wrong policy? Start with
p=noneto monitor before enforcing stricter policies (quarantineorreject).
🛠 Step 2: Validate SPF and DKIM
DMARC depends on SPF and DKIM. If either fails, DMARC enforcement will too.
✅ SPF Check:
Run this:
nslookup -type=TXT yourdomain.com
Ensure your SPF record includes all legitimate mail servers:
v=spf1 include:_spf.google.com ~all
Common SPF Issues:
Multiple SPF records? Merge them into one.
Missing sending IPs? Add them using
include:.
✅ DKIM Check:
Find your selector (e.g., default) and run:
nslookup -type=TXT default._domainkey.yourdomain.com
Expected output:
v=DKIM1; k=rsa; p=MIIBIjANBgkqh... (public key)
Common DKIM Issues:
DKIM not configured? Enable it in your email provider’s settings.
Incorrect selector? Use the right DKIM selector for your domain.
📊 Step 3: Analyze DMARC Reports
DMARC reports provide valuable insights into authentication failures.
✅ Aggregate Reports (RUA):
Check your inbox for reports from your rua= email. Use tools like DMARCian or Postmark to visualize data.
✅ Forensic Reports (RUF):
These provide detailed insights into failed authentication attempts.
Common Issues:
No reports? Ensure your
ruaandrufemails are valid.Emails from unexpected sources? Investigate unauthorized senders.
🔗 Step 4: Align SPF, DKIM, and DMARC Policies
For DMARC to pass, at least one alignment must succeed.
✅ Ensure Alignment:
SPF Alignment: The
From:domain should match the SPF domain.DKIM Alignment: The
From:domain should match the DKIM signing domain.
Use this tool to check:
dmarcian.com/dmarc-inspector/
Common Fixes:
Enable relaxed alignment (
aspf=randadkim=rin your DMARC record).Update your mail server settings to ensure proper alignment.
🛑 Step 5: Debug Rejected or Quarantined Emails
If legitimate emails are failing DMARC, check:
Email Headers: Use Gmail’s "Show Original" to inspect SPF, DKIM, and DMARC results.
Mail Server Logs: Look for authentication failures in logs.
Policy Settings: Start with
p=nonebefore enforcing stricter policies.
🎯 Final Thoughts
Fixing DMARC issues can be complex, but with a structured approach, you can pinpoint and resolve them efficiently. If you’re stuck, tools like YourDMARC can simplify monitoring and compliance.
Need help? Our team is here to assist you in ensuring your email security is bulletproof! 🔐
🚀 Pro Tip: Stay Compliant and Secure
Regularly monitor your DMARC reports and gradually enforce p=quarantine or p=reject once everything is properly configured. This prevents unauthorized senders from misusing your domain.
Happy debugging! 🚀