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IP, DNS & privacy guides
Deep dives on IP fraud, DNS, edge caching and the plumbing of your connection.
Mail in the Spam Folder? Check Three Things About the Sending IP
PTR, SPF lookup limits and DMARC ordering — the three checks that explain most delivery failures before anyone rewrites the copy.
How You Get Identified: Proxy Verdicts, TLS Fingerprints and Bot Scores
Three layers of evidence, from the network that carries you to the shape of your handshake to the score attached to your behaviour. Each is weaker than it sounds.
The IP a Website Sees: Type, Ownership and Location
Three questions in order — what kind of address it is, who is registered for it, and where it claims to be. Each answers something different, and the third is the least reliable.
A Captcha Is Not a Security Control, It Is a Cost Allocation
Who really pays for a challenge, why false positives cluster on the users you can least afford to lose, and what to deploy instead.
Two Kinds of DNS Protection: DNSSEC for Integrity, Encrypted DNS for Privacy
They solve different problems and are routinely confused. One proves the answer was not altered; the other hides the question. Neither does both.
How Long You Keep Logs Is a Privacy Decision You Already Made
Access logs are the largest personal-data store most small projects have, and almost nobody chooses its retention on purpose.
IP Reputation: How Scores Are Calculated, and Why a New Server Arrives With a Record
A score estimates what the address looks like right now, from what it did before. Those two clauses explain both the number and its failures.
Two Leak Tests Everyone Should Run: WebRTC and DNS
A VPN can hide your address and still leave two doors open. Both are measurable in a browser, and both are usually misconfigured by default.
Dual-Stack Networks: Why You Only See One Address
IPv4 and IPv6 coexist in silence. Here is how to check both, and what a missing family tells you.