Why DMARC Authentication Checks Fail and How to Prevent It

Why DMARC Authentication Checks Fail and How to Prevent It

ByBrad Slavin

DMARC authentication checks typically fail because of DNS record errors, SPF lookup/limit and alignment issues, DKIM signature and key problems, strict alignment choices, third‑party sender misconfigurations, forwarding/mailing‑list rewrites, and mail‑gateway alterations—and you prevent them by validating DNS, staying within SPF limits, configuring DKIM correctly, choosing appropriate alignment modes, enforcing vendor controls, deploying ARC for indirect…

How to Check a Link for Phishing — by DMARCReport

How to Check a Link for Phishing — by DMARCReport

ByBrad Slavin

Phishing attacks are one of the most pervasive and effective online threats today — whether you’re an individual, a small business, or a global enterprise. Attackers craft convincing emails, messages, and links that disguise malicious intent under a veneer of legitimacy. Their objective is simple: get you to click a link, open a file, or…

Scan Carefully First, Education Under Threat, AI Phishing Surge

Scan Carefully First, Education Under Threat, AI Phishing Surge

ByBrad Slavin

Last week was all about phishing attacks that targeted naive users left, right, and center. Research findings revolved around an upsurge in AI-backed phishing attacks, while experts have noticed phishing QR codes as an emerging threat in the cybersecurity landscape. Meanwhile, India has been experiencing 3,100 phishing attacks per week. The silver lining in the…

Which reporting formats and tools are best for analyzing DMARC alignment reports?

Which reporting formats and tools are best for analyzing DMARC alignment reports?

ByBrad Slavin

For analyzing DMARC alignment reports at scale, the most effective stack is to ingest standard aggregate RUA XML with privacy-governed RUF samples, normalize everything into structured JSON, and analyze it in a purpose-built platform like DMARCReport (or an open-source parsedmarc + ELK/Splunk stack) that delivershigh parsing accuracy, enrichment, dashboards, alerting, and seamless integrations. DMARC alignment…

Types of Phishing Domains Every Security Team Should Blacklist

Types of Phishing Domains Every Security Team Should Blacklist

ByBrad Slavin

Phishing isn’t a distant risk anymore — it’s a daily reality for enterprises, governments, small businesses, and individual users alike. Scammers have become shockingly good at blending into legitimate digital communication, with phishing URLs and look-alike domains that trick even cautious users. That’s why an effective email security strategy must include blacklisting malicious domains and…

Understanding the Top 8 Most Common DNS Record Types — A Comprehensive Guide by DMARCReport

Understanding the Top 8 Most Common DNS Record Types — A Comprehensive Guide by DMARCReport

ByBrad Slavin

The internet runs on many unseen systems working together to deliver content, route email, and keep your domain functioning securely and reliably. One of the most foundational but overlooked elements of this infrastructure is the Domain Name System (DNS) — particularly the DNS records that determine how your domain behaves across the internet. At DMARCReport,…

How can I find the DKIM selector and public key used by my Google Apps domain?

How can I find the DKIM selector and public key used by my Google Apps domain?

ByBrad Slavin

To find the DKIM selector and public key used by your Google Apps (Google Workspace) domain, open the Admin console (Apps > Google Workspace > Gmail > Authenticate email) to read the active selector, send yourself an email and inspect the DKIM-Signature header’s s= value, then query DNS for TXT at <selector>._domainkey.<your-domain> (e.g., google._domainkey.example.com) via…

What does an “invalid DKIM signature” result mean when shown by a checker?

What does an “invalid DKIM signature” result mean when shown by a checker?

ByBrad Slavin

An “invalid DKIM signature” result means the message contains a DKIM-Signature header but the verifier cannot validate it—typically because the computed header/body hashes don’t match what was signed or because the public‑key lookup/cryptographic verification fails—so the signature is untrusted. DKIM (DomainKeys Identified Mail) asserts message integrity and domain authentication by hashing specific headers and the…

Why are DKIM keys important for email deliverability and anti-spoofing?

Why are DKIM keys important for email deliverability and anti-spoofing?

ByBrad Slavin

DKIM keys are important for email deliverability and anti-spoofing because they let receivers cryptographically verify that the visible From-domain authorized the message and that headers/body were not altered, enabling DMARC alignment that boosts inbox placement while blocking spoofing—even across forwarding and mailing lists. Context and background DomainKeys Identified Mail (DKIM) is a signature framework defined…

When should I start reviewing DMARC aggregate reports after implementing a DMARC policy?

When should I start reviewing DMARC aggregate reports after implementing a DMARC policy?

ByBrad Slavin

Start reviewing DMARC aggregate (RUA) reports within 24–48 hours of publishing your DMARC record—immediately upon receipt of the first reports—and continue daily reviews for at least 14–30 days (30–60 days for large enterprises) before moving from p=none to quarantine/reject, using DMARCReport automation to catch early issues and validate readiness. Context: What DMARC Aggregate Reports Are…

Commission MDM Breach, Singapore Cyber Alliance, Senegal DAF Breach

Commission MDM Breach, Singapore Cyber Alliance, Senegal DAF Breach

ByBrad Slavin

Here’s the bulletin for week 2 in February. Last week focused on cyberattacks targeting critical infrastructure, including the European Commission and Singapore’s telecommunications sector. Meanwhile, multiple crypto users have fallen prey to address poison scams. Also, the Senegal threat attack managed to disrupt crucial government services, leading to panic and confusion. European Commission’s mobile device…

When should I implement DKIM if I already have SPF and DMARC configured?

When should I implement DKIM if I already have SPF and DMARC configured?

ByBrad Slavin

You should implement DKIM immediately—even if SPF and DMARC are already configured—because DMARC enforcement and reliable deliverability depend on a DKIM-aligned signature that survives forwarding and third-party relays. SPF authenticates the connecting IP but commonly breaks on forwarding; DMARC only passes if either SPF or DKIM aligns with the visible From domain, so leaving out…

Tools Used During a DDoS Attack — A Comprehensive Guide

Tools Used During a DDoS Attack — A Comprehensive Guide

ByBrad Slavin

In today’s digitally connected landscape, Distributed Denial of Service (DDoS) attacks represent one of the most disruptive and persistent threats to online infrastructure. Whether the target is a global e-commerce platform, a government portal, a small business website, or a cloud-based application, DDoS attacks aim to drain resources, block legitimate traffic, and render services unavailable…

How does a DKIM DNS record protect my domain from email spoofing?

How does a DKIM DNS record protect my domain from email spoofing?

ByBrad Slavin

A DKIM DNS record protects your domain from email spoofing by publishing a public key (under a selector) that receivers use to verify the cryptographic signature in your email’s DKIM-Signature header, proving the message was authorized by your domain, detecting tampering, and enabling DMARC alignment so unauthenticated spoofs can be quarantined or rejected. DKIM (DomainKeys…

The History of Email: From ARPANET to Modern Secure Communication

The History of Email: From ARPANET to Modern Secure Communication

ByBrad Slavin

Email is one of the most transformative technologies in the history of digital communication. Although it may seem like a mundane tool you use every day to send messages, share files, or coordinate with teams, email’s evolution is a remarkable journey that spans decades of innovation, expansion, and adaptation. Today, more than 300 billion emails…

How does DKIM verification differ from SPF and DMARC in protecting email?

How does DKIM verification differ from SPF and DMARC in protecting email?

ByBrad Slavin

DKIM verification protects email by cryptographically validating that selected headers and the body were unaltered and bound to the domain in the d= tag, while SPF only checks whether the sending IP is authorized for the envelope domain and DMARC enforces policy by requiring domain alignment of a passing DKIM or SPF result with the…