GUIDES
In-depth explainers on networking, security and cloud topics — one new guide a week
Written the same way the tools on this site are built — by someone who actually does this for a living, not summarised from someone else's blog post. Each guide stands on its own; the tools linked at the bottom of each one are there if you want to go apply what you just read, not the other way around.
No guides match that search.
Hardware
Sizing a UPS Properly: The Math Vendors Don't Explain
Why the runtime number on the box is measured under conditions your actual load will never match, and how to size for reality instead.
Developer
Cron Expressions: The Parts Everyone Gets Wrong
The day-of-month/day-of-week OR-logic that catches almost everyone out at least once, and the other cron gotchas that don't show up until 3am.
Developer
JWTs Explained: What's Actually Inside a Token
Header, payload, signature — what each part does, why the payload is readable by anyone (and always has been), and what actually keeps a JWT trustworthy.
Security
A Field Guide to TLS/SSL Certificate Errors
What NET::ERR_CERT_AUTHORITY_INVALID, expired, self-signed, hostname mismatch and chain errors each actually mean, and how to tell them apart fast.
Networking
DNS Propagation, Demystified
What's actually happening — and what isn't — in the hours after you change a DNS record, and why "it hasn't propagated yet" is usually the wrong explanation.
Security
Password Hashing: Why Bcrypt, Not Just SHA-256
The difference between a fast hash and a deliberately slow one, and why using the wrong kind for password storage is a genuinely common, genuinely serious mistake.
Server & Cloud
Why Your Cloud Bill Spirals, and How to Actually Read It
The line items that quietly dominate an AWS/Azure/GCP bill, and why the sticker price on compute is rarely the real story.
Storage
RAID Levels Explained: Which One for Which Workload
RAID 0, 1, 5, 6 and 10 aren't interchangeable choices — what each actually trades off, and how to pick based on the workload instead of habit.
Security
How CVSS Scores Actually Work — and Where They Mislead You
What the base, temporal and environmental metrics actually measure, and why a 9.8 on paper doesn't automatically mean drop everything.
Networking
Subnetting From Scratch: Planning a VLSM Addressing Scheme
How to actually think through a Variable Length Subnet Mask design instead of memorising CIDR tables — sizing subnets to fit, not just fitting subnets to a chart.
Security
SPF, DKIM & DMARC — Actually Explained
Three different email authentication records that get lumped together constantly, and what each one actually does when a message shows up in someone's inbox.