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Technical writeups on SSL, email authentication, uptime monitoring, networking, and whatever else we had to dig into this week.

The True Cost of Each Extra Nine of Uptime

Uptime numbers show up everywhere — pitch decks, status pages, marketing sites. The numbers are easy to write. What they actually cost to deliver, and how you would prove you hit them, is something most teams never get around to thinking about.

April 27, 2026 8 min read

How to Set Up DMARC for a New Domain (Without Breaking Your Email)

DMARC is the last layer of email authentication. Done right, it stops spoofing of your domain. Done wrong, it silently drops your own legitimate email. Here is the order of operations that avoids breaking anything.

April 20, 2026 6 min read

Freshping Shut Down — What Now?

Freshworks permanently shut down Freshping on March 6, 2026. If you're one of the 20,000+ businesses that relied on it for free uptime monitoring, here's what happened, what your options are, and how to migrate.

April 1, 2026 3 min read

Are Domains and SSL Certificates Case Sensitive? Sometimes.

Everyone assumes domain names and SSL certificates are completely case-insensitive. They're mostly right. But there are real-world situations where capitalization changes what certificate you get back, and most people have no idea.

March 19, 2026 3 min read

Netwatch: A Lightweight Internet Outage Monitor for OPNsense That Actually Sends Alerts

OPNsense's built-in tools can detect when your internet goes down, but they can't reliably tell you about it. Monit drops alerts when the network is down. Postfix queuing is fragile on FreeBSD. So I wrote a shell script that handles its own email queue and collects diagnostics at the moment of failure.

February 25, 2026 5 min read

OPNsense Failover Kills States When No Viable Failover Target Exists

Months of stable OPNsense operation, then intermittent DNS hangs across every device. The cause: dpinger declaring the WAN gateway down based on ISP latency, triggering state killing with no failover target. The bug report was closed as a "configuration issue."

February 16, 2026 6 min read

Stripe Says Publishable Keys Are Safe to Expose. They're Not.

Stripe's documentation says publishable keys are "not secret" and safe to embed in client-side code. But attackers are using them to validate stolen credit cards at scale - and Stripe blames the merchants.

January 1, 2026 5 min read

Safari Hanging on Page Reloads? OPNsense, QUIC.

Spent a week debugging Safari hanging on page reloads. Turns out it was my OPNsense firewall's UDP timeout killing idle QUIC connections. Here's how to fix it.

December 2, 2025 6 min read

MacBook Slow on 5GHz WiFi? Change Your Router's Channel.

My MacBook Pro M3 was barely hitting 40 Mbps on 5GHz with constant packet loss. Every other device was fine. The fix was the router's 5GHz channel. Changed it from 149 to 40 and instantly hit 1.1 Gbps.

February 21, 2025 4 min read