Corporate Email Security: Stopping Spoofing and BEC with SPF, DKIM and DMARC

Quick answer: Most cyber attacks start with email, and among the most dangerous are fake emails sent in your name. When someone writes to your customer from an address that looks like "[email protected]", without the right controls the fake is delivered as if real, impersonating your brand and defrauding your customer. Three DNS records, SPF, DKIM and DMARC, prevent unauthorized use of your domain. These are the minimum of modern email security, not optional. DSET sets up your records, analyzes reports and moves you safely to a "reject" policy: +90 536 662 38 09.

Why email is such a critical, fragile door

SMTP "trusts" the sender by design and does not verify identity; the sender address is as easy to fake as writing any name on an envelope. Attackers abuse this via:

  1. Spoofing: impersonating your domain to your customers and staff.
  2. BEC (Business Email Compromise): one of the costliest cyber crimes, impersonating an executive for an "urgent transfer" or a supplier claiming "our IBAN changed." No malware, only abused trust and urgency. The FBI's IC3 reports BEC among the highest financial loss crimes for years.

SPF, DKIM, DMARC

Record What it does Analogy
SPF Lists which servers may send for your domain "Authorized couriers"
DKIM Cryptographically signs outgoing mail "An unbroken seal"
DMARC Sets policy when SPF/DKIM fail, plus reports "Reject fakes and report to me"

DMARC's three policy levels (the critical part)

  1. p=none (monitor only): good start to see who sends as you, but no protection.
  2. p=quarantine: unverified mail goes to spam, the first real protection.
  3. p=reject: fakes never reach the recipient, the goal.

Most common mistake: setting DMARC and leaving it at "none," feeling protected. Real protection starts at quarantine/reject. But jumping straight to reject without identifying all legitimate senders (CRM, billing, marketing, third parties) can drop your own real mail, so move gradually using the reports. That is where the expertise lies.

Email security is more than DNS

  • Advanced filtering for malicious attachments, links and phishing.
  • Staff awareness and a reflex to verify "urgent transfer" requests via a second channel (phone). This one rule stops most BEC.
  • MFA as the second door if the account itself is targeted. See IAM.

See our email security solution.

FAQ

Is setting these up hard?

Adding records is short; the expertise is identifying all legitimate senders and moving DMARC to reject without dropping real mail.

Do these reduce inbound spam?

Their direct goal is stopping outbound spoofing; a side benefit is better deliverability. Inbound spam needs separate filtering.

Does a small business need DMARC?

Absolutely; impersonation and BEC happen at every scale, and it also improves deliverability of your invoices and quotes.

Best defense against "IBAN changed" emails?

Verify any payment/IBAN change via a known trusted channel, not the number in the email.

Reach us for email authentication setup and a safe DMARC reject migration: +90 536 662 38 09.

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