4 Systems & infrastructure
Every entry filed under Systems & infrastructure and its subtopics.
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What do these mean?
- Beginner
- You are new to this topic.
- Intermediate
- You use it, and want to get better.
- Advanced
- You know it well and need the details.
- Guided project
- Build something small from start to finish, step by step.
- Explains an idea
- Plain words on how something works and why.
- Step by step
- Numbered steps to get one task done.
- Cheat sheet
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- Fixes an error
- An error message, what it means, and how to solve it.
27 entries match these filters
- 0455 Which security tool does what? A map for beginners A beginner's map of open source security tool families: vulnerability scanners, secret detection, static analysis, host audits, web application testing, network inventory… Beginner · Explains an idea · Any system Article Security resources & detection · Server hardening 15 Oct 2026
- 0443 Security monitoring explained: IDS, SIEM, EDR and where the logs go A plain language map of the security monitoring tool families, what each one watches, how they feed one another, and where the… Beginner · Explains an idea · Any system Article Detection & threat hunting · Logs 15 Oct 2026
- 0431 What is a detection rule? Sigma explained for beginners A detection rule describes one kind of suspicious activity in logs. Sigma is the shared, tool-independent way to write such rules, so… Beginner · Explains an idea · Any system Article Alerting & dashboards · Security resources & detection 15 Oct 2026
- 0433 What is an awesome list? Awesome lists are hand-curated link collections on GitHub, one per subject, that follow a shared convention. How they work, how to tell… Beginner · Explains an idea · Any system Article Security resources & detection 15 Oct 2026
- 0355 TLS certificates explained What a certificate proves, who signs it, what the chain and expiry mean, and how to read any site's certificate from the… Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0362 The 3-2-1 backup rule, and why a backup you never restored is not a backup Three copies, two kinds of media, one off-site: what the rule really protects against, how it maps to real tools, and why… Beginner · Explains an idea · Any system Article Strategy & restore drills 15 Oct 2026
- 0310 What is a cluster? A cluster is a group of computers working together as one system so that if one fails the others keep the service… Beginner · Explains an idea · Any system Article Clusters & high availability 15 Oct 2026
- 0311 What is Kubernetes? Kubernetes is a system that runs containers across many servers, restarting, scaling and connecting them automatically. Beginner · Explains an idea · Any system Article Concepts 15 Oct 2026
- 0312 What is a pod? A pod is the smallest unit Kubernetes runs: one or more containers that share a network address and storage. Beginner · Explains an idea · Any system Article Workloads & services 15 Oct 2026
- 0291 What is a log? A log is a running record of what a program did and when, written to a file so you can look back… Beginner · Explains an idea · Any system Article Logs 15 Oct 2026
- 0306 What is hashing? Hashing turns any data into a fixed length fingerprint that cannot be reversed, used to check files and store passwords. Beginner · Explains an idea · Any system Article Secrets & access 15 Oct 2026
- 0307 What is encryption? Encryption scrambles data with a key so only someone with the right key can read it again. Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0308 What is a backup snapshot? A snapshot is a frozen picture of a disk or system at one moment that you can roll back to if something… Beginner · Explains an idea · Any system Article Strategy & restore drills 15 Oct 2026
- 0309 What is RAID? RAID combines several disks into one so data survives a disk failure or is read and written faster. Beginner · Explains an idea · Any system Article Disks, LVM & filesystems 15 Oct 2026
- 0268 What is a container? A container is a lightweight box that packs a program with everything it needs so it runs the same on any computer. Beginner · Explains an idea · Any system Article Docker basics 15 Oct 2026
- 0272 What is a virtual machine? A virtual machine is a complete computer made of software, running inside another computer with its own operating system. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
- 0273 What is a hypervisor? A hypervisor is the software layer that creates and runs virtual machines and shares the real hardware between them. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
- 0274 What is DNS? DNS is the internet's phone book: it turns names like example.com into the IP addresses computers actually use. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026
- 0275 What is an IP address? An IP address is the unique number that identifies a device on a network so data knows where to go. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026
- 0276 What is SSH? SSH is a secure way to open a command line on another computer over the network, with everything encrypted. Beginner · Explains an idea · Any system Article SSH 15 Oct 2026
- 0277 What is TLS? TLS is the encryption layer that puts the S in HTTPS, protecting data between your browser and a server. Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0278 What is a certificate? A certificate is a digital ID card that proves a website or server is genuine, issued by a trusted authority. Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0280 What is a firewall? A firewall is a filter that decides which network connections are allowed in or out of a computer or network. Beginner · Explains an idea · Any system Article Firewalls 15 Oct 2026
- 0281 What is a package manager? A package manager is a tool that installs, updates and removes software for you and keeps track of what depends on what. Beginner · Explains an idea · Any system Article Packages & updates 15 Oct 2026
- 0288 What is a daemon or service? A daemon or service is a program that runs in the background all the time, waiting to do its job without a… Beginner · Explains an idea · Any system Article Services & systemd 15 Oct 2026
- 0266 What is a port? A port is a numbered door on a computer that lets one machine run many network services at the same time. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026
- 0187 Terraform concepts: providers, state, plan and apply, modules, and OpenTofu Terraform describes infrastructure in code, compares it with what exists, and changes only the difference. Learn providers, resources, state, the plan/apply loop,… Beginner · Explains an idea · Any system Article Terraform 15 Oct 2026