Phishing Emails: Definition, Deliverability Risks, and Prevention
Learn what phishing emails are, why they damage sender trust and deliverability, and how authentication, monitoring, and response reduce risk.
Oct 20, 202620 min read
Email Security
34 articles on email security.
Quarantined Email: Meaning, Causes, and How to Prevent It
Learn what a quarantined email is, why security filters hold messages, how it affects deliverability, and how senders can prevent it.
Oct 20, 202624 min read
SSL Certificate in Email Sending: What It Means for Deliverability
Learn what an SSL certificate means in email sending, how TLS validates servers and tracking links, and how to prevent certificate-related delivery failures.
Oct 19, 202623 min read
AI Agent Email Security: How to Defend Inboxes From Autonomous Agents
AI agent email security is now essential. Learn how to protect inboxes, APIs, credentials, and workflows from prompt injection and rogue agents.
Oct 18, 202624 min read
DMARC Monitoring: How to Read Reports and Fix Email Authentication
Learn DMARC monitoring: configure aggregate reports, interpret SPF and DKIM alignment, identify unknown senders, and safely enforce policy.
Oct 18, 202620 min read
RFC 8058 One-Click Unsubscribe: Why GET Can Break Your Email List
Implement RFC 8058 one-click unsubscribe safely: why GET requests cause accidental opt-outs, how POST works, and how to secure your endpoint.
Oct 15, 202622 min read
Email Worm: Definition, Risks, and Prevention for Senders
Learn what an email worm is, how it spreads through mailboxes, why it harms deliverability, and how senders can prevent email worm abuse.
Sep 15, 202624 min read
Email Spoofing: Definition, Examples, and Prevention
Email spoofing is forged sender identity in a message. Learn how SPF, DKIM, and DMARC help stop impersonation and protect deliverability.
Sep 14, 202623 min read
Email Gateway: Definition, How It Works, and Deliverability Impact
Learn what an email gateway is, how it routes and filters mail, why it affects deliverability, and how senders troubleshoot gateway errors.
Sep 12, 202625 min read
Email Encryption: What It Means for Secure Email Delivery
Learn what email encryption means, how TLS, MTA-STS, DANE, and end-to-end encryption protect email delivery and affect campaign operations.
Sep 11, 202623 min read
Email Blacklist: What It Means for Deliverability and How to Fix It
Learn what an email blacklist is, why listings damage deliverability, how to diagnose the cause, and the practical steps to get delisted.
Sep 10, 202623 min read
Bot Detection in Email: A Deliverability and Analytics Guide
Learn how bot detection in email separates security scans and privacy fetches from real engagement, so you can trust clicks, opens, and campaign results.
Sep 2, 202623 min read
How Often Should You Generate a New DKIM Key?
Learn how often to generate a new DKIM key, when emergency rotation is required, and how to rotate selectors without breaking email delivery.
Aug 15, 202619 min read
What Is SPF and Why Is It Important for Email?
Learn what SPF is, how SPF DNS records work, why it matters for email security and deliverability, and how to configure and test it correctly.
Aug 15, 202622 min read
How to Ensure Sensitive Data Isn’t Stored on Resend
Learn how to ensure sensitive data isn’t stored on Resend or any email provider with safer templates, logging controls, DNS, and retention practices.
Aug 13, 202620 min read
Opportunistic TLS vs Enforced TLS: What’s the Difference in Email?
Learn how opportunistic TLS vs enforced TLS affects SMTP email delivery, downgrade resistance, DNS records, failures, and deliverability.
Aug 12, 202620 min read
Email Authentication for Office 365: SPF, DKIM, and DMARC Setup Guide
Set up email authentication for O365 with SPF, DKIM, and DMARC. Use real DNS record examples, test headers, and fix common failures.
Aug 5, 202619 min read
Transactional Email Security: A Practical Guide to Protecting Every Send
Learn transactional email security step by step: authenticate domains, protect API keys and links, verify webhooks, and monitor every send.
Aug 3, 202621 min read
Email Authentication Check: Verify SPF, DKIM, and DMARC Step by Step
Run an email authentication check for SPF, DKIM, and DMARC. Find DNS errors, inspect headers, fix alignment, and prove your domain passes.
Aug 2, 202618 min read
Email Authentication Settings: Configure SPF, DKIM, and DMARC Correctly
Set email authentication settings correctly with SPF, DKIM, and DMARC. Use DNS record examples, tests, and fixes to protect delivery.
Aug 2, 202621 min read
DMARC Record Example: Copy, Configure, Test, and Enforce
Use this DMARC record example to publish the right DNS TXT record, monitor SPF and DKIM alignment, fix failures, and safely reach p=reject.
Aug 1, 202618 min read
DMARC Record Check: How to Validate, Fix, and Test Your DNS Policy
Run a DMARC record check, read the DNS result, fix common syntax and alignment errors, and verify your email policy works before enforcing it.
Aug 1, 202617 min read
DMARC Record Checker: Check, Interpret, and Fix Your DMARC Record
Use a DMARC record checker to find, validate, interpret, and fix your DNS policy. Includes syntax, alignment tests, errors, and a worked example.
Jul 28, 202617 min read
DMARC Record Creator: Build, Publish, and Validate Your DMARC Policy
Use this DMARC record creator guide to build correct DNS syntax, collect reports, move safely to enforcement, and validate your email authentication.
Jul 28, 202619 min read
DMARC Record Microsoft 365: Complete Setup, Testing, and Enforcement Guide
Set up a DMARC record for Microsoft 365 with correct SPF, DKIM, reporting, testing, and a safe path from monitoring to enforcement.
Jul 28, 202619 min read
DMARC Record Errors: How to Find, Fix, and Prevent Them
Fix DMARC record errors with a practical checklist for DNS syntax, SPF and DKIM alignment, reporting, policies, testing, and validation.
Jul 27, 202621 min read
Email Authentication Methods: SPF, DKIM, and DMARC Explained
Learn email authentication methods with SPF, DKIM, and DMARC record examples, rollout steps, testing checks, and fixes for common failures.
Jul 27, 202620 min read
Email Authentication Records: Set Up SPF, DKIM, and DMARC Correctly
Learn how to create, validate, and troubleshoot email authentication records for SPF, DKIM, and DMARC with practical DNS examples.
Jul 26, 202623 min read
Email Authentication DMARC: Setup, Alignment, Reports, and Fixes
Set up email authentication DMARC correctly: align SPF and DKIM, publish DNS records, read reports, fix failures, and move safely to reject.
Jul 26, 202621 min read
SMTP Relay for Scan to Email: Setup, Security, and Troubleshooting
Set up SMTP relay for scan to email with Microsoft 365, Google Workspace, or an SMTP provider. Get ports, DNS, security, testing, and fixes.
Jul 26, 202622 min read
DMARC Record Setup: A Practical DNS Guide From Monitoring to Reject
Set up a DMARC record with correct DNS syntax, SPF and DKIM alignment, reporting, staged enforcement, testing, and fixes for failures.
Jul 26, 202620 min read
Email Authentication Protocols: A Practical SPF, DKIM, DMARC and ARC Guide
Learn how email authentication protocols work, configure SPF, DKIM, DMARC and ARC records, diagnose failures, and protect your domain from spoofing.
Jul 26, 202620 min read
SPF, DKIM, and DMARC Setup: A Practical DNS Guide That Works
Learn SPF DKIM DMARC setup step by step: create correct DNS records, validate alignment, monitor reports, and safely enforce anti-spoofing.
Jul 25, 202619 min read
Stripo Incident Is a Reminder That Your Email Stack Holds the Keys to Your Sender Reputation
The Stripo security incident shows why ESP API keys need rotation, least privilege, and monitoring. Follow steps to protect your sender reputation.
Jul 24, 2026