Why Do We Need SPF, DKIM, and DMARC?
- Attackers can send fake emails using your domain.
- Customers may receive phishing emails that appear legitimate.
- Your domain reputation can be damaged.
- Legitimate emails may end up in spam folders.
- Implementing SPF, DKIM, and DMARC helps prevent these issues and improves email security.
1️⃣ SPF (Sender Policy Framework)
SPF is an email authentication method that specifies which mail servers are authorized to send emails on behalf of your domain.
It works by publishing a TXT record in your DNS.
How SPF Works
- You send an email.
- The receiving mail server checks your domain's SPF record.
- It verifies whether the sending server's IP address is authorized.
If authorized → PASS
If unauthorized → FAIL
Example SPF Record
v=spf1 include:_spf.google.com ip4:203.0.113.5 -all
What SPF Protects Against
✅ Email Spoofing
✅ Unauthorized Mail Servers
✅ Phishing Attempts
Limitation
SPF verifies who sent the email, but it does not verify whether the email content was modified.
2️⃣ DKIM (DomainKeys Identified Mail)
- DKIM adds a digital signature to outgoing emails.
- This signature proves that:
- The email was sent by an authorized sender.
- The email content was not modified during transit.
How DKIM Works
- Your mail server signs the email using a private key.
- The public key is stored in DNS.
- The recipient's mail server retrieves the public key.
- The signature is validated.
- If valid → Email is trusted.
Example DKIM Record
selector1._domainkey.example.com
v=DKIM1; k=rsa; p=PUBLIC_KEY
Benefits of DKIM
✅ Ensures Email Integrity
✅ Prevents Email Tampering
✅ Improves Deliverability
✅ Supports Email Forwarding
Limitation
DKIM verifies authenticity and integrity but does not decide whether a failed email should be accepted or rejected.
3️⃣ DMARC (Domain-based Message Authentication, Reporting & Conformance)
- DMARC builds upon SPF and DKIM.
- It tells receiving mail servers what action to take when an email fails authentication checks.
- DMARC also provides valuable reporting that helps domain owners monitor email activity.
How DMARC Works
- Email is received.
- SPF validation runs.
- DKIM validation runs.
- DMARC evaluates the results.
- Policy is applied.
Example DMARC Record
v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com
DMARC Policies
p=none
Monitor only
No action taken
p=quarantine
Suspicious emails may be sent to spam/junk
p=reject
Failed emails are rejected completely
Benefits of DMARC
✅ Protects Against Domain Impersonation
✅ Reduces Phishing Attacks
✅ Improves Brand Trust
✅ Provides Authentication Reports
✅ Enhances Email Deliverability
Email security is no longer optional—it's a necessity. SPF, DKIM, and DMARC work together to protect your domain from spoofing, phishing, and unauthorized email usage.
- SPF verifies who is allowed to send emails on behalf of your domain.
- DKIM ensures that the email content remains unchanged during transit.
- DMARC enforces policies and provides visibility into authentication failures.
🔒 Secure your email. Protect your domain. Build trust.
Thanks for reading! If you found this helpful, feel free to share your experience with SPF, DKIM, and DMARC in the comments
