Module 3: Scanning Networks

Section 1: Network Scanning Concepts

Network scanning is the automated process of searching for accessible devices and services on a network. It follows footprinting in the ethical hacking methodology.

Section 2: Host Discovery

Techniques to determine which systems are alive: ping sweeps, ARP requests, ICMP timestamp requests.

Section 3: Port and Service Discovery

Methods to identify open ports and services: TCP connect scan, SYN stealth scan, UDP scan, XMAS scan, NULL scan, FIN scan. Tools include Nmap, Nessus, OpenVAS.

Section 4: OS Discovery

OS fingerprinting uses TCP/IP stack characteristics. Tools: Nmap OS detection, p0f.

Section 5: Scanning Beyond IDS and Firewall

Evasion techniques including fragmentation, decoy scanning, spoofing, and using alternate network paths to avoid detection.