Blog
Guides, tutorials, and best practices for email authentication and domain protection.
Lookalike Domains: How Attackers Impersonate Your Brand and How to Detect Them
Cybercriminals register domains that closely resemble yours to trick customers and employees. Learn how lookalike domain attacks work and how to monitor for them.
Email Authentication for SaaS Companies: A Practical Guide
SaaS companies send email from many sources — transactional, marketing, support, and product notifications. Here's how to configure SPF, DKIM, and DMARC across all of them.
MTA-STS: Enforcing TLS Encryption for Email in Transit
Learn how MTA-STS prevents TLS downgrade attacks by requiring encrypted connections for email delivery. Includes setup guide, policy modes, and troubleshooting tips.
Subdomain Spoofing: Why You Need DMARC on Every Subdomain
Attackers don't just spoof your main domain — they target subdomains too. Learn how DMARC subdomain policies work and how to protect your entire domain namespace.
The SPF 10-Lookup Limit: Why It Exists and How to Fix It
Understand why SPF is limited to 10 DNS lookups, what happens when you exceed it, and practical strategies including SPF flattening to stay within the limit.
BIMI: Display Your Brand Logo in Email Inboxes
A complete guide to BIMI (Brand Indicators for Message Identification) — how it works, requirements, VMC certificates, and how to set it up for your domain.
TLS-RPT Explained: Monitoring Your Email Encryption
Learn what TLS-RPT (TLS Reporting) is, how it complements MTA-STS, and how to use TLS reports to ensure your email connections are properly encrypted.
Email Forwarding and DMARC: Why Forwarded Emails Fail and How ARC Helps
Understand why email forwarding breaks SPF and sometimes DKIM, how it impacts DMARC authentication, and how ARC (Authenticated Received Chain) solves the problem.
What Are DMARC Failure Reports (RUF) and Should You Enable Them?
Understand DMARC forensic (RUF) reports — what data they contain, how they differ from aggregate reports, privacy considerations, and when they are worth enabling.
How to Move from DMARC p=none to p=reject Safely
A step-by-step playbook for tightening your DMARC policy from monitoring mode to full enforcement without breaking legitimate email flows.
DKIM Explained: How Email Signatures Prevent Spoofing
Learn how DKIM works under the hood — from key generation and DNS publishing to message signing and verification — and why it matters for email deliverability.
SPF Record Syntax Explained: A Complete Reference
A thorough breakdown of every SPF mechanism, qualifier, and modifier with real-world examples to help you write correct SPF records the first time.
What is DMARC? A Complete Guide to Email Authentication
Learn what DMARC is, how it works with SPF and DKIM to protect your domain from email spoofing, and why every organization needs it.
SPF vs DKIM vs DMARC Explained: What's the Difference?
Understand the differences between SPF, DKIM, and DMARC, how they work together, and why you need all three for complete email authentication.
How to Set Up DMARC Step by Step
A practical walkthrough for implementing DMARC on your domain, from initial monitoring to full enforcement, with real DNS record examples.
Understanding DMARC Reports: A Practical Guide
Learn how to read and interpret DMARC aggregate (RUA) and forensic (RUF) reports to monitor your email authentication and identify threats.
DMARC Policy: None vs Quarantine vs Reject — Which to Choose?
Understand the three DMARC policy levels, when to use each one, and how to safely progress from monitoring to full enforcement.