Hardening the network you already run. Articles tagged Network Security cover control-plane protection, access control, segmentation, and the attacks each countermeasure is actually stopping.
Nmap -O fingerprints a host's TCP/IP stack to guess its operating system, no login and no banner required. Learn what it measures, how to read every field it prints, and why it fails in predictable ways on lab gear and appliances.
Nmap -sV turns port 80 open into nginx 1.29.8. This guide covers what version detection actually sends, how to read the fingerprint results, and how to tune intensity when it guesses wrong.
ACK, FIN, NULL, Xmas, Window, and Maimon: what each Nmap TCP scan type detects, which flags it sets, and where each one lies to you when the target stack does not play by the rules.
How the SYN scan works, how it differs from a connect scan, how to choose which ports to hit, and the lesson that matters most: reading open, closed, and filtered correctly instead of guessing.
How Nmap decides a host is up: ping sweeps, ARP on local networks, and when to reach for -Pn. Learn why discovery differs for local and remote targets and how to read the results like an engineer auditing your own gear.