Every week, businesses miss out on opportunities because their emails never reach the recipient. An invoice, a quote, a follow-up message — all filtered or blocked before being seen. The recipient has no idea. Why? Email servers flag them as suspicious.
The root cause is often the absence of three essential protections: SPF, DKIM, and DMARC. These acronyms may sound technical, but their job is straightforward: protect your domain’s identity and ensure your emails are trusted and delivered.
In this article, we break down how these three protocols work together, and why any business that sends emails needs to implement them. No jargon, just clarity.
Why Your Emails Aren’t Always Delivered
When you send an email, the recipient’s server checks a few things. Gmail, Outlook, Apple Mail and others ask: Can we trust this sender? Was the message altered? Is the server authorized to send it?
Without clear proof, your email is either blocked or sent to the junk folder.
That proof comes from SPF, DKIM and DMARC. They tell servers, “Yes, this message is legitimate and safe.”
SPF: Who’s Allowed to Send Emails From Your Domain?
SPF (Sender Policy Framework) lets you specify which servers are authorized to send emails using your domain name. Think Microsoft 365, your marketing platform, or your invoicing system.
You publish this information in your DNS. It’s a public declaration email servers can read.
If a cybercriminal tries to spoof your domain from an unauthorized server, SPF flags it.
But SPF alone can’t stop tampered messages. And it only works when the email header is correctly aligned. That’s why SPF is just one piece of the puzzle.
DKIM: The Invisible Signature That Proves Authenticity
DKIM (DomainKeys Identified Mail) works like a digital signature. When you send an email, it’s signed using a private key. On the receiving end, mail servers can verify the signature with a public key published in your DNS.
This proves two things: the message wasn’t altered, and it came from a trusted domain.
It’s like sealing every message with a digital wax stamp.
Important: For business domains (like yourcompany.ca), DKIM is never enabled by default. You must activate it manually in your Microsoft 365, Google Workspace, or other platform admin console, and publish the public key.
DMARC: The Orchestrator of Your Email Security
DMARC (Domain-based Message Authentication, Reporting and Conformance) ties SPF and DKIM together. It lets you define what should happen when a message fails authentication: should it be delivered, quarantined or rejected?
You can start with a relaxed policy (“none”) to monitor your setup, then gradually move to stricter rules (“quarantine” or “reject”).
DMARC also sends you reports. These show which services are using your domain to send emails, so you can catch misconfigurations or suspicious activity.
Why You Need All Three
SPF alone can be bypassed. DKIM by itself is incomplete. DMARC is powerless without them.
Used together, these protocols:
- Improve email deliverability.
- Prevent cybercriminals from impersonating your domain.
- Boost your brand credibility.
- Reduce the risk of impersonation attacks like CEO fraud and targeted phishing.
Together, they form a robust barrier against identity spoofing. Want to dive deeper into CEO fraud? Check out our related article here.
How to Implement Them Step-by-Step
- List every service that sends email on your behalf (CRM, website, marketing platform, etc.).
- Create an SPF record in your DNS including all authorized platforms.
- Enable DKIM in your email platform and publish the public key.
- Set up a DMARC record in “none” mode. Review reports, then enforce stricter policies.
There are free online tools that can check your SPF, DKIM and DMARC settings. Microsoft, Google and most hosting providers offer support.
A Simple Setup With Powerful Impact
SPF, DKIM and DMARC aren’t just for large corporations. They’re essential for any SME that uses email.
They’re easy to set up, often free, and make a huge difference. Your emails get delivered. Your reputation is protected. Your clients feel confident.
In 2026, this is no longer optional. It’s the baseline.
Not sure if your domain is protected? The experts at Mon Technicien can help. We already assist many Quebec SMEs in securing their communications and improving email performance.
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