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Deliverability & DNS

SPF, DKIM, DMARC setup guides, DNS record configuration, inbox placement troubleshooting, and deliverability monitoring for self-hosted email.

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Domain Reputation: How It Breaks and How to Fix It (2026)

Domain Reputation: How It Breaks and How to Fix It (2026)

Domain reputation breaks faster than it builds. This guide covers the 0.3% spam complaint cliff, SPF/DKIM/DMARC alignment traps, the Yahoo inbox-denominator death spiral, Google's high-water mark rule, and the step-by-step recovery plan to pay down reputation debt.

· Alexey Bulygin
SPF Record Setup: Examples, Generators & Common Failures

SPF Record Setup: Examples, Generators & Common Failures

A broken SPF record means SMTP 550 rejections, not just spam folder placement. This guide covers single-domain setup, agency multi-sender patterns, the 10-lookup limit, flattening vs. segmentation, and the failure modes that cause 80% of deliverability tickets.

· Alexey Bulygin
DMARC Record: Setup, Alignment, Reports, and Rollout Guide

DMARC Record: Setup, Alignment, Reports, and Rollout Guide

A DMARC record tells receiving servers what to do when email fails authentication. This guide covers setup, the three policy levels, alignment mechanics, safe rollout strategy, reporting, and managing DMARC at scale across multiple domains.

· Alexey Bulygin
Why Emails Go to Spam: Fix Deliverability Beyond DNS (2026)

Why Emails Go to Spam: Fix Deliverability Beyond DNS (2026)

Perfect authentication scores but emails still land in spam? The real culprits in 2026 are complaint rates, shared IP reputation, provider-specific rules, and infrastructure isolation. Here's what actually fixes deliverability.

· Alexey Bulygin
Email Authentication SPF DKIM DMARC: Why Green Checks Still Fail

Email Authentication SPF DKIM DMARC: Why Green Checks Still Fail

Setting up SPF, DKIM, and DMARC is the entry ticket, not the finish line. This guide covers the real email authentication failure modes — alignment traps, the 10-lookup limit, FCrDNS, one-click unsubscribe requirements, and the 0.3% spam complaint cliff that kills domains.

· Alexey Bulygin
DKIM Record: Setup, Selectors, Key Rotation, and Failure Debugging

DKIM Record: Setup, Selectors, Key Rotation, and Failure Debugging

A DKIM record publishes a public cryptographic key that proves your email wasn't tampered with in transit. This guide covers setup, selectors, the 255-character DNS problem, key rotation, failure troubleshooting, and CNAME-based automation at scale.

· Alexey Bulygin
Email Deliverability: Authentication, Reputation, and Fixes (2026)

Email Deliverability: Authentication, Reputation, and Fixes (2026)

Email deliverability is an infrastructure problem. This guide covers the authentication stack (SPF, DKIM, DMARC), reputation economics, provider-specific intelligence for Gmail/Outlook/Yahoo, and a 24-hour triage plan to get out of the spam folder.

· Alexey Bulygin
DMARC RUA: Setup, Reports, and Fixes

DMARC RUA: Setup, Reports, and Fixes

DMARC RUA is the reporting address that makes DMARC useful. Here’s how to publish it, read the reports, and fix the failures that hurt deliverability.

· Alexey Bulygin
DKIM Key: Best Length, DNS Setup, and Rotation

DKIM Key: Best Length, DNS Setup, and Rotation

Your DKIM key is either helping delivery or quietly breaking it. Here’s the operator guide to 2048-bit keys, DNS splitting, selector rotation, and when TrekMail saves time.

· Alexey Bulygin

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