The DMARC tag that meant 10% of the time now means all the time
RFC 9989 removed the pct tag in May 2026, and the same document says receivers must ignore tags that are not registered....
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The lookalike domain that is blocked on .com and shown on .ru
The famous all-Cyrillic apple.com impersonation was patched in 2017 and the matter filed as closed. Both major browsers...
How to Self-Host Gitea or Forgejo with Docker
The environment variable that closes public registration was renamed, so copying an older tutorial leaves your git host...
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What an ID number's check digit actually proves
The last character of most identity numbers is computed from the ones before it, using a published formula anyone can ap...
How to Set Up Caddy as a Reverse Proxy with Docker
Caddy gets certificates without being asked, which is why it is the right first reverse proxy. The confusion starts with...
How to Self-Host Vaultwarden with Docker
The compose file is trivial. The admin token is not: it wants an Argon2 hash rather than a password, and the hash then b...
How to Stop ChatGPT, Claude, Gemini and Grok Training on Your Chats (2026)
Four switches with almost the same name, doing four different things. Three are on by default. One also sets your retent...
Why CSV Libraries Do Not Stop Formula Injection
The same six values written by Python, by PHP, and by joining strings with commas. The libraries fix the commas and the...
Which Image Operations Strip Metadata
A source image with six identifying tags and GPS coordinates, put through eight operations. Pillow drops everything unle...
What Your Rate Limit Actually Limits
A route limited to 30 a minute and one limited to 60 turned out to share a single counter, because the framework keys it...
How to Stop an Agent Returning Documents the User Should Not See
A vector search scoped three ways, and measured each time. Unfiltered, four in five results belonged to another team; fi...
How Old Is the Code You Installed?
The median package in this site's tree was published 286 days ago — but one in five has seen no release in two years, an...
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