Proactive alerts: Prevent DMARC failures before they happen

Why DMARC needs proactive alerts

DMARC is a continuous process, not a checkbox. Even when you’ve done the hard work of mapping senders and aligning SPF and DKIM, the environment keeps shifting.

New tools appear without warning

A new CRM, marketing platform, or ticketing system can start sending messages using your domain with very little friction. Sometimes it’s a formal project. Sometimes it’s not.

If that sender isn’t authenticated correctly, an enforced DMARC policy will quarantine or reject messages that don’t align. That is good for stopping spoofing, but it can break legitimate communication when new sending services are added outside your visibility. 

The problem is that failures rarely announce themselves in a helpful way:

• Under p=quarantine, delivery issues can look like “low engagement” or “no response,” because messages are diverted to a Spam or Junk folder.
• Under p=reject, you typically discover it through bounces, user complaints, and disrupted operations.

DNS is fragile under pressure

Most DMARC failures that “come out of nowhere” aren’t mysterious. They usually trace back to a small change in the DNS or sender configuration.

Common examples include:

• The SPF record is updated to add a new service, but a syntax error breaks evaluation.
• The SPF record is “cleaned up” to simplify DNS, and a legitimate sender is removed by mistake.
• The DMARC policy is tightened, but one legitimate sending service hasn’t been authorized.

If you only discover these issues through reports or delayed investigation, you’re always reacting. Proactive alerts close the gap between “something changed” and “someone fixed it.”

DMARC reports help, but they’re not instant

DMARC aggregate reports are valuable for visibility, but they don’t always provide the fast feedback teams need. Many teams still need to collect reports, parse XML, identify the sender, confirm whether it’s legitimate, and then trace the fix back to the DNS.

Proactive alerts don’t replace reporting. They complement it by telling you immediately when a change is likely to affect authentication.

How proactive alerts monitor key events

Domain inclusion

When a new domain enters your environment, it’s often unprotected by default. A proactive alert can flag the domain early so you can set up authentication before it’s used.

That usually includes:

• Publishing an SPF record that reflects authorized senders
• Enabling DKIM signing for the platforms that send email
• Adding a DMARC record that starts in monitoring (p=none) and progressing safely

New senders

This alert is the one that prevents the “we didn’t know this existed” moment.

A new sender showing up could be:

• A legitimate service launched without IT involvement
• A vendor that changed its infrastructure without notice
• An unauthorized sender that’s attempting to use your domain

The response is different depending on which scenario it is, but the value is the same. You get the signal early, while the impact is still limited.

SPF, DKIM, and DMARC record modifications

Proactive alerts flag changes to critical DNS records so you can review them quickly and fix issues before they affect authentication and deliverability, whether the change was planned or not.

Lookalike domains

Lookalike domains are a common precursor to impersonation campaigns. Proactive alerts help your team respond early, before the domain is used to target customers, suppliers, or your internal teams.

Even with a strong DMARC policy on your own domain, lookalikes can still create confusion. Early warning gives you time to respond quickly – request takedowns and warn users.

Impact of proactive alerts vs. reactive management

Reactive DMARC management is familiar to most teams:

• Users report missing emails, bounces, or “it went to Junk.”
• IT investigates under pressure.
• The root cause turns out to be a new sender or DNS change.
• A fix is made quickly, sometimes without proper validation.
• The same pattern repeats when the next tool is introduced.

Proactive alerts break that cycle. They surface the change first, so you can act before the company feels it.

Fewer deliverability incidents during enforcement

When you move to p=quarantine or p=reject, small changes have bigger consequences. Proactive alerts reduce the chance you’ll only spot misconfigurations after email flows start failing.

That matters most for high-impact email streams like:

• Invoices and statements
• Password resets
• Customer notifications and service updates
• Internal operational messages (approvals, tickets, alerts)

Faster alignment when new tools are introduced

New senders are inevitable. The goal is to onboard them cleanly.

Proactive alerts flag new senders as soon as they show up. That gives you time to confirm who owns the service, validate that it’s legitimate, and make the necessary DNS updates before enforcement starts diverting or blocking messages.

More confidence in DMARC policy progression

Many teams stall at p=none because they’re worried enforcement will break legitimate email. That fear is reasonable if you’re relying on slow feedback loops and manual reporting, instead of proactive alerts.

Proactive alerts make enforcement safer because they give you early visibility into the DNS changes that typically cause DMARC failures.

Book a demo to see how Sendmarc’s proactive alerts help you detect DNS changes, identify new senders early, and progress to DMARC enforcement with confidence.