Your Guide to Email Security and Deliverability
Email authentication isn’t exactly thrilling dinner conversation, but if your business depends on email (and whose doesn’t?), it matters more than ever. Gmail, Outlook, and Yahoo have all started enforcing stricter rules about which emails they’ll actually deliver. If you’re not set up correctly, your messages might never make it to the inbox—or worse, someone could impersonate your company in phishing attacks.
The good news? Three protocols—SPF, DKIM, and DMARC—handle most of the heavy lifting. Here’s what they do and why you should care.
SPF (Sender Policy Framework)
The Bouncer at the Door
SPF is basically a list you publish that says “these mail servers are allowed to send email on behalf of my domain.” When someone receives an email claiming to be from you, their mail server checks this list. If the sending server isn’t on it, that’s a red flag.
It’s straightforward: you’re telling the world which servers you actually use to send email. This makes it much harder for spammers to fake messages from your domain.
Why it matters: Without SPF, anyone can pretend to send email from your company. That’s not great for your reputation—or your customers’ security.
DKIM (DomainKeys Identified Mail)
The Tamper-Proof Seal
DKIM adds a digital signature to your outgoing emails. Think of it like a wax seal on an old letter—if someone opens it and changes the contents, you’ll know.
When your mail server sends an email, it signs it with a private key. The receiving server uses your public key (which you publish in DNS) to verify the signature. If the email’s been tampered with, the signature won’t match.
Why it matters: DKIM proves your email is authentic and hasn’t been modified in transit. It’s another layer of protection that helps receiving servers trust your messages.
DMARC (Domain-based Message Authentication, Reporting, and Conformance)
The Policy Enforcer
DMARC ties SPF and DKIM together and tells receiving servers what to do if an email fails those checks. Should they deliver it anyway? Quarantine it? Reject it outright?
More importantly, DMARC gives you visibility. It generates reports showing you who’s sending email on your behalf—both legitimate services and bad actors trying to abuse your domain.
Why it matters: DMARC is where you actually enforce your email authentication policy. It’s the difference between knowing someone’s trying to spoof your domain and being able to stop them.
Understanding DMARC Reports
DMARC reports show which emails passed or failed authentication checks. These reports are XML files delivered daily—sometimes hundreds or thousands of them depending on your email volume. They weren’t designed to be read by humans.
The format is deliberately machine-readable because DMARC reporting was built for automated systems to process. Trying to review these manually is like trying to read server logs line-by-line—technically possible, but not practical or sustainable.
This is exactly why most organizations use a managed DMARC service. The service ingests all those XML reports, parses the data, and presents it in a way that actually makes sense. You get alerts when something needs attention, regular summaries of what’s happening, and the ability to take action without deciphering XML schemas.
What These Reports Actually Tell You
- Unauthorized senders - Someone trying to spoof your domain
- Legitimate services failing authentication - Maybe you forgot to authorize a new email platform
- Patterns in failures - Issues with your SPF or DKIM configuration
The value is in catching these problems before they hurt deliverability or let phishing emails through—but realistically, that requires automation to handle the volume and complexity.
How They Work Together
These three protocols form a complete system:
SPF checks if the mail server is authorized. DKIM verifies the message is authentic and unmodified. DMARC enforces your policy when those checks fail and tells you what’s happening.
None of them are bulletproof alone, but together they make it significantly harder for bad actors to abuse your domain—and help ensure your legitimate emails actually get delivered.
Why This Matters More Now Than It Used To
Starting in 2024, major email providers aren’t asking nicely anymore. Google, Yahoo, and Microsoft now require DMARC for successful email delivery in most cases. What was once a best practice is now a hard requirement.
Emails that fail authentication checks are increasingly likely to land in spam—or not get delivered at all. The days of loosely configured email systems getting a pass are over.
And there’s the security angle: if you don’t implement DMARC with enforcement, someone will eventually try to spoof your domain. Whether that’s a phishing campaign targeting your customers or a random spammer—it’ll hurt your reputation.
Getting This Set Up
The basics aren’t too complicated, though the details can get tricky depending on your setup:
- Add an SPF record to your DNS listing your authorized mail servers
- Enable DKIM on your mail server and publish the public key in DNS
- Create a DMARC policy that starts in monitoring mode, then tighten it as you verify everything works
- Set up automated DMARC report processing through a managed service—manual review isn’t practical at any meaningful scale
The hardest part is the ongoing monitoring. DMARC reports come in daily by the hundreds or thousands, in XML format designed for machines, not humans. This is why most organizations hand this piece off to a managed service from the start.
How We Can Help
At 2Fifteen Tech, we handle email authentication for businesses that have better things to do than read XML reports. We’ll set up SPF, DKIM, and DMARC correctly the first time, then monitor everything to make sure it stays that way.
We offer fully managed DMARC service that handles the daily reporting, identifies issues before they cause problems, and adjusts your policies as your email infrastructure evolves. You get regular updates on what’s happening, and we handle the technical details.
If you’re just curious where things stand, try the domain scanner below to check your current setup. It’ll show you what’s configured (or missing) and give you a starting point.