Learn how to find hosts, open ports and services with a single powerful command-line tool. 16.04.2026 | reading time: 2 min Nmap is the command-line tool to discover hosts, scan ports and identify services on a network; it helps to map infrastructure and to perform basic security audits quickly and reliably. Hands-on scan example Run a SYN scan with version and OS detection as root: ```sudo nmap -sS -sV -O -p 22,80,443 -T4 192.0.2.10``` Example condensed output: ```Starting Nmap 7.80... Nmap scan report for 192.0.2.10 Host is up (0.0012s latency). PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 7.4 80/tcp open http Apache httpd 2.4.6 443/tcp open https OpenSSL 1.0.2 Service detection performed. OS detection results: Linux 3.x.``` Beyond the first scan Try different scan types and options to answer specific questions: use `-sU` for UDP, `-sS` for stealthy TCP SYN, `-sV` to probe service versions, `-O` for OS detection, `-sC` or `--script` for NSE scripts and `-Pn` to skip host discovery; combine timing (`-T4`) and output options (`-oA`) to automate workflows. Real use cases Use Nmap to inventory hosts, find unexpectedly open services, validate firewall rules and run lightweight vulnerability checks with NSE scripts; it scales from single-host diagnostics to network-wide sweeps when paired with proper timing and filtering. Tools that play well with Nmap Pair Nmap with packet capture and analysis to verify findings, use mass scanning tools for very large ranges, and bring results into scripts or dashboards; common complements include packet sniffers, port scanners and simple TCP tools. Final note Practice responsibly on networks you own or are authorized to test; Nmap is powerful and reveals real weaknesses when used correctly, so keep scans documented and permissioned and then expand skills toward certification with focused study and lab work at bitsandbytes.academy for CompTIA Linux+ or LPIC-1 preparation. Join Bits & Bytes Academy First class LINUX exam preparation. network security utilities troubleshooting infrastructure
