Our blog shares expert insights on email security, DMARC configuration, and deliverability optimization.
A 2026 field guide to complaint feedback headers: Gmail Feedback-ID, Yahoo CFL enrollment, Microsoft SNDS/JMRP, Apple iCloud Mail, Comcast FBL, and RFC 9477 CFBL-Address.
An MX record is the DNS entry that tells the rest of the internet which mail servers receive email for a domain. Here is how MX records work, what each field means, and why priority matters.
Three ways to look up MX records for any domain: a free MX records lookup tool, dig and nslookup from a terminal, and a few lines of Ruby or Python.
Seeing queued in Gmail usually means your message is waiting in the Outbox because Gmail cannot send it yet. Here are the common causes, safe fixes, and when to check SPF, DKIM, or DMARC.
We published five troubleshooting guides covering SPF errors, DKIM failures, alignment issues, forwarding breakage, and the full p=none to p=reject migration. Each one follows the same format: symptom, diagnosis, solution, prevention.
The Return-Path is not the address your users see, but it still plays a critical role in email authentication. Learn how the SMTP envelope, SPF, bounces, and DMARC alignment fit together.
Every include in your SPF record costs a DNS lookup. Hit 10 and every email from your domain fails SPF. The SPF Optimizer resolves your includes into IPs automatically so you never blow the budget.
Marketing agencies, MSPs, and IT consultants face a unique challenge: implementing DMARC at scale. One client is manageable. Twenty clients, each with their own ESPs, DNS providers, and compliance requirements? That requires a system.
SPF failures show up in your DMARC reports or email headers, but the reason is not always obvious. We break down the common causes of SPF failures and walk through practical troubleshooting steps.
Gmail now requires DMARC for bulk senders. Learn how to check if your domain passes Google's email authentication requirements, fix common issues, and monitor your DMARC status.
Sending emails is no longer enough. Gmail, Yahoo, and Microsoft now require authentication, clean lists, and proper reputation. Here's the complete stack to ensure your emails actually reach the inbox.
Marc's note on the product choice behind our SPF generator: show the lookup budget early, treat provider presets carefully, and never pretend a browser estimate is live DNS validation.
Hire an email deliverability consultant who has shipped billions of emails. Free assessment, hands-on engagement, written quote before any work starts.
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