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September 10, 2026 How to Check Your SPF Record (and Fix What Is Wrong) How to check an SPF record for a sending domain, what the ten-lookup limit does, why two SPF records break authentication entirely, and how to fix each failure. Read article → September 10, 2026 The Real Cost of Cold Email Infrastructure at 10, 100 and 500 Mailboxes Three routes priced side by side, including the one nobody writes about, with the crossover points worked out. Read article → September 10, 2026 Rolling Out DMARC: none, quarantine, reject A staged DMARC rollout for cold email senders: what to publish first, how to read aggregate reports, when to move to quarantine and reject, and how to avoid blocking your own mail. Read article → September 10, 2026 How to Run a Domain Health Check How to run a domain health check before a sending domain goes live: the four records that matter, what an A to F grade is measuring, and the order to fix problems in. Read article → September 10, 2026 How to Run an Inbox Placement Test How to run an inbox placement test properly: what it measures that delivery rate cannot, how to read the results by provider, how often to test, and what to change when you land in spam or promotions. Read article → September 10, 2026 MX and DNS Record Lookup for Cold Email How to look up MX, TXT, A, NS and CNAME records for a sending domain, what each one tells you, and the misconfigurations a lookup reliably catches. Read article → September 10, 2026 Shared IP vs Dedicated IP: The Volume Threshold That Decides It When a shared IP beats a dedicated one, the volume threshold where that flips, and the five questions that separate a managed pool from an open one. Read article → September 10, 2026 How to Check Your DKIM Record How to check a DKIM record, why you need the selector to look one up, what a valid key looks like, and the failures that break signing silently. Read article → September 10, 2026 How to Check Your DMARC Record How to check a DMARC record, what each policy value does, what alignment means, and why p=none is a monitoring state rather than protection. Read article → September 2, 2026 Domain Rotation for Cold Email: How It Works and When to Use It What domain rotation actually protects you from, how to structure a domain fleet, when rotation helps and when it is a workaround for a problem you should fix instead. Read article →