Engineering guides
Practical, tested explanations of the networking, Linux and security questions behind each LocalSecTools utility. Written and reviewed by Asad Ali, IT Support Engineer (Microsoft SC-200, ISC2 CC).
All guides
Networking7 min readPrivate IP Ranges (RFC 1918) and Subnet Mask to CIDR: A Practical Guide
The three RFC 1918 blocks, why 255.255.255.0 is a /24, and how to size and split /16, /22, /23 and /24 networks without overlaps.Read the guide
Networking6 min read/30 vs /29 vs /28 vs /27 Subnet Masks: Host Bits Explained
Masks, host bits and usable hosts for /25 through /30, plus the exam question: how many host bits does 255.255.255.224 leave?Read the guide
Linux6 min readchmod 000, 400, 555, 600, 666 and 770: Linux Permissions Guide
Six chmod modes that matter in real systems, from locked-down 000 and SSH-key 400 to shared-team 770, with audit commands for risky permissions.Read the guide
Linux6 min readCrontab Every 5 Minutes, Every 15 Minutes and Every 4 Hours (plus systemd Timers)
Copy-ready crontab lines for every 5 and 15 minutes, hourly and every 4 hours, the matching systemd timers, and the mistakes that make cron jobs fail.Read the guide
Vulnerability management6 min readCVSS 4.0 Score Calculator vs CVSS 3.1: What Changed in Vulnerability Scoring
CVSS 3.1 vs 4.0 side by side: what was added, what was removed, how the 4.0 score is calculated and how to score a CVE in practice.Read the guide
Security operations6 min readAn Offline SecOps Workflow: Log De-obfuscation, IOC Defanging, KQL Hunting and DMARC
Follow one phishing-to-PowerShell alert from decoding to DMARC hardening, using browser-only tools so evidence never leaves your machine.Read the guide
About the author: Asad Ali
IT Support Engineer and SOC analyst · Microsoft SC-200 & ISC2 CC certified
Asad Ali is an IT Support Engineer and SOC analyst with a Computer Science degree from UET Lahore. He holds the Microsoft SC-200 Security Operations Analyst and ISC2 Certified in Cybersecurity (CC) certifications, works on threat detection, network analysis and Linux administration, and builds and maintains every tool on LocalSecTools.
- Microsoft Certified: Security Operations Analyst (SC-200)
- ISC2 Certified in Cybersecurity (CC)
Every guide is written and technically reviewed by Asad Ali, and the commands and numbers are checked against the LocalSecTools calculators. Read more about his work at asadali.tech.