Articles & guides
Explainers, how-to guides and the occasional news note. The answer comes first, always, then the numbers, diagrams and sources for going deeper.
Dev News
Anthropic Suspends Claude Fable 5 and Mythos 5
Anthropic disabled Claude Fable 5 and Mythos 5 worldwide after a US government order. The timeline, the trigger, and how to fall back to Opus 4.8 fast.
Security
AI in Cybersecurity 2026: Real vs Hype, Both Sides
AI in cybersecurity in 2026: what it really does for defenders (triage, summarization, code review), what attackers do with it, and the dual-use problem.
Security
Bug Bounty Starter Guide for Sysadmins
A bug bounty starter guide for sysadmins: how your DNS, HTTP and Linux skills transfer, the five free tools I open, and the report shape that gets paid.
Dev Guide
Build a Local AI Agent with Ollama + Qwen 2.5
How I run a local AI agent with Ollama and Qwen 2.5 in 2026: install on Windows, Linux or macOS, pick the model your VRAM fits, call it from Python and LangChain.
Sysadmin Guide
CentOS to Rocky Linux 9 Migration Playbook 2026
CentOS to Rocky Linux 9 migration, end to end: the in-place ELevate route, the fresh-install route, the pre-flight inventory, and the breaks that fail silently.
Dev
ChatGPT vs Claude vs Gemini 2026
A hands-on ChatGPT vs Claude vs Gemini comparison for 2026, ten real jobs tested through the APIs: code, research, writing, data, vision, cost and latency.
Sysadmin Guide
The chmod and chown Cheatsheet, Decoded
A practical Linux chmod and chown cheatsheet: the Permission denied fix with chmod +x, why 755 and 644 keep showing up, chown for ownership, and recursing safely.
Dev
Claude Fable 5 vs Opus 4.8: One Day In
Claude Fable 5 vs Opus 4.8 after a mid-session swap on launch day: 95.0% vs 88.6% SWE-bench, exactly 2x the price, and the safety routing caveat.
Sysadmin
Choosing a Linux Distribution in 2026: Decision Guide
Choosing a Linux distribution in 2026 without the tribal noise: four inputs that decide (team skills, compliance, app stack, support) plus honest distro profiles.
SEO
Core Web Vitals 2026: LCP, INP and CLS Mastery
Master Core Web Vitals in 2026: what LCP, INP and CLS really measure, lab vs field data, the fixes that still hold up, plus budgets and a weekly workflow.
Sysadmin Guide
Build a CTF Lab on Hyper-V: Full Walkthrough
Build a CTF lab on Hyper-V: three trust-segmented virtual switches, a Kali attacker, Metasploitable3 and a broken Windows 10, with pfSense in the middle for routing.
Dev Guide
curl Cheatsheet: Download Files and Test APIs
A practical curl cheatsheet: download and keep the remote name with curl -O, follow redirects with -L, fetch headers only with -I, and POST JSON with -d.
Network Guide
DNS over HTTPS Implementation Guide
DNS over HTTPS the way I roll it out: what DoH buys you (and what it does not), flipping it on for Windows, Linux and macOS, plus self-hosting and edge enforcement.
Sysadmin Guide
Fix: ESXi Host Not Responding in vCenter
ESXi host Not Responding in vCenter is almost always a dead management link, not a dead host. Restart hostd then vpxa, clear the log partition, check ports 902/443.
Dev Guide
The find Command Cheatsheet: Recipes You Actually Use
A practical Linux find cheatsheet: find by -name, big files with -size +100M, recent ones with -mtime, delete with -delete, and run -exec on each hit.
Dev Guide
Git Rebase vs Merge: A Visual Workflow Guide
Git rebase vs merge, decided in one mental model and five real situations: branch diagrams before and after, the exact commands, and the rule I never break.
Dev Guide
The grep Cheatsheet: Search a File, Search a Tree
A practical Linux grep cheatsheet: search one file with grep pattern file, search a whole tree with grep -rn, ignore case with -i, invert with -v, and pick -E or -F.
Sysadmin Guide
Hyper-V: The Hypervisor Is Not Running, Fix Guide
Fix Hyper-V 'the hypervisor is not running' by working the five gates in order: BIOS virtualization, the feature, hypervisorlaunchtype, conflicts, services.
SEO Guide
How I Optimize Images for Website Speed in 2026
Image optimization techniques for 2026: why AVIF goes first with WebP and JPEG behind it, responsive srcset, the lazy-load plus LCP trap, compression, and CDN automation.
SEO
INP Optimization 2026: Fix Interaction to Next Paint
A hands-on INP optimization guide for 2026: the twelve Interaction to Next Paint killers I keep finding in audits, how to profile them, and a real 480ms to 120ms fix.
Network Guide
iptables vs nftables: A Linux Firewall Cheatsheet
iptables vs nftables, side by side: list rules, allow SSH on dport 22, default drop policy, persist to rules.v4 or nftables.conf, convert with iptables-translate.
Network
Linux Firewall Comparison 2026: ufw, nftables, iptables
Linux firewall comparison for 2026: iptables, nftables, firewalld and ufw all poke one kernel. Per-distro defaults, the same rule four ways, plus my honest pick.
Security Guide
Linux Kernel Hardening: sysctl Checklist
Linux kernel hardening with sysctl: the 32 toggles I actually ship, grouped by subsystem and sorted by how much each one matters, plus a drift check.
Network Guide
Linux Networking Commands: ip and ss Cheatsheet
ifconfig and netstat are gone on most modern Linux installs. The iproute2 replacements you need: ip a, ss -tulpn, ip route, ip neigh, and a clean old-to-new map.
Network
MikroTik vs Ubiquiti for Home Networks (2026)
MikroTik vs Ubiquiti for a prosumer home network: matched stacks under 400 EUR, CLI vs UI, real routing protocols, Wi-Fi roaming, VPN, a 3-year cost breakdown.
SEO Guide
Mobile Optimization 2026: Fast and Findable on Phones
Mobile optimization in 2026: the Core Web Vitals targets for mobile (LCP under 2.5s, INP under 200ms, CLS under 0.1), what slows a phone, and how to test like one.
Network
Network Config Across Linux Distros in 2026
Network config across Linux distros in 2026: netplan, ifupdown, NetworkManager, systemd-networkd and wicked compared, with the static IP recipe for each.
Network Guide
nmcli Cheatsheet: Manage Wi-Fi From the Terminal
A practical nmcli cheatsheet for NetworkManager: scan and connect to Wi-Fi, list saved connections, bring them up and down, check device status, and set a static IP.
Network
pfSense vs OPNsense for Home Networks (2026)
pfSense vs OPNsense for home networks, run side by side on one N100 mini-PC for years: UI, update cadence, plugins, real benchmarks, appliances, and which I pick.
Network Guide
PowerShell Networking Cheatsheet for Windows
A PowerShell networking cheatsheet: test a port with Test-NetConnection, read your IP and DNS with Get-NetIPConfiguration, find listening ports, resolve names.
Sysadmin
Proxmox vs ESXi vs Hyper-V in 2026: Which to Run
Proxmox vs ESXi vs Hyper-V in 2026: honest cost, licensing, clustering, backup and containers after the Broadcom shakeup, plus which fits homelab or enterprise.
Dev Guide
Python regex cheatsheet: 20 essential patterns explained
A Python regex cheatsheet of 20 tested re patterns: email, IPv4 and IPv6, URL, phone, ISO 8601, UUID, CSV split, log lines, slugs, with the edge case for each.
Sysadmin Guide
The rsync Cheatsheet: Mirror, Sync and Copy Over SSH
A practical Linux rsync cheatsheet: mirror with rsync -av, copy over ssh with -avz, mirror exactly with --delete, dry-run, resume, and the trailing slash gotcha.
Security Guide
Ubuntu 24.04 Server Hardening: SysAdmin Checklist
Ubuntu 24.04 server hardening, the way I run it on every VPS: keys-only SSH on a quiet port, UFW, fail2ban, unattended updates, AppArmor enforcing, auditd.
Network Guide
Self-Hosted VPN with WireGuard: Setup Guide
Self-hosted WireGuard VPN on a 5 EUR VPS: pick split vs full tunnel, generate Curve25519 keys, write the server and client configs, and get NAT and DNS right.
Security Guide
SOC Homelab with Wazuh, Suricata and ELK
Build a SOC homelab with Wazuh, Suricata and the Elastic Stack on a spare VM: the single-node installer, agent enrolment, and test attacks you can fire yourself.
Sysadmin Guide
Nagios on Hyper-V: Server Monitoring Setup Guide
Server monitoring with Nagios on a Hyper-V Ubuntu 24.04 VM: build Nagios 4.5 from source, aim HTTP, SSH, MySQL and disk probes, then wire mail and Telegram alerts.
Sysadmin Guide
SSH Command Cheatsheet: Connect, Keys, scp, Tunnels
A practical SSH command cheatsheet, most-used first: connect with ssh user@host, make an ed25519 key, push it with ssh-copy-id, copy files with scp, tunnel ports.
Sysadmin Guide
SSH Permission Denied (publickey): The Fix
Permission denied (publickey) is never mysterious once you read the handshake. The real causes in order, each with the exact command to confirm and fix it.
Sysadmin Guide
systemctl and journalctl Cheatsheet
A systemctl and journalctl cheatsheet: status to see if a service runs and why it died, restart, reload, enable --now, daemon-reload, and journalctl -u NAME -f.
Network
Tailscale vs WireGuard in 2026: Not Competitors
Tailscale vs WireGuard in 2026: Tailscale is WireGuard plus a control plane for keys, NAT traversal via DERP, MagicDNS and ACLs. When each one wins.
Sysadmin Guide
The tar Command Cheatsheet: Create, Extract, List
A practical Linux tar cheatsheet: create a gzip archive with tar -czf, extract with tar -xzf (eXtract Ze File), list with tar -tzf, plus exclude and strip-components.
SEO Guide
Core Web Vitals 2026: Fix LCP, INP and CLS (Real Code)
Core Web Vitals in 2026: before/after code I shipped for LCP, INP and CLS, reading a Lighthouse capture honestly, plus the WordPress and Cloudflare toggles I reach for.
Security Guide
Vaultwarden Self-Host Guide: Bitwarden in 20 Minutes
Vaultwarden self-host guide: docker compose plus Caddy with automatic TLS, your first admin signup, then fail2ban, restic backups, and locking down the admin route.
Sysadmin Guide
VMware ESXi PSOD: Diagnose and Recover the Host
VMware ESXi PSOD fix guide: read the purple screen, tell a bad driver from dying hardware, grab the coredump before you reboot, then recover the host.
Sysadmin Guide
VMware Workstation and Hyper-V on the Same PC (2026)
The VMware Device/Credential Guard not compatible error has two fixes: keep Hyper-V and upgrade VMware to Workstation 16+, or disable Hyper-V and VBS for VMware 15.
Security Guide
Wazuh SIEM on a Budget: Pi, N100 or Cloud
Wazuh SIEM on a budget, three paths I actually run: a Raspberry Pi 5 under 100 EUR, an Intel N100 mini-PC, or a Hetzner CAX21 ARM node under 10 EUR a month.
SEO Guide
Web Accessibility and WCAG in 2026
Web accessibility in 2026: target WCAG 2.2 AA, fix the five issues that sink most sites (contrast, alt text, labels, link text, page language), and test it yourself.
Dev Guide
Web Workers in 2026: Patterns, Pitfalls and INP
Web Workers in 2026: the patterns I reach for, the ones I skip, transferables, SharedArrayBuffer, Comlink, and how to prove the move actually helped your INP.
Security Guide
Web App Security Audit 2026: A Practical Method
The web app security audit I actually run in 2026, in four layers: transport, app code, supply chain, secrets, with the tools and a 25-point checklist.
Security Guide
WordPress Security Audit in 10 Steps (2026)
A WordPress security audit you run in about 90 minutes: PHP and WP versions, plugin CVEs, HTTP headers, htaccess, TLS, 2FA, xmlrpc, user enumeration, logs and backups.