Option Explanation
-sL List scan – list targets without scanning
Host Discovery
-sn Ping scan – host discovery only
Port Scanning
-sT TCP connect scan – complete three-way handshake
-sS TCP SYN – only first step of the three-way handshake
-sU UDP Scan
-F Fast mode – scans the 100 most common ports
-p[range] Specifies a range of port numbers – -p- scans all the ports
-Pn Treat all hosts as online – scan hosts that appear to be down
Service Detection
-O OS detection
-sV Service version detection
-A OS detection, version detection, and other additions
Timing
-T<0-5> Timing template – paranoid (0), sneaky (1), polite (2), normal (3), aggressive (4), and insane (5)
--min-parallelism <numprobes> and --max-parallelism <numprobes> Minimum and maximum number of parallel probes
--min-rate <number> and --max-rate <number> Minimum and maximum rate (packets/second)
--host-timeout Maximum amount of time to wait for a target host
Real-time output
-v Verbosity level – for example, -vv and -v4
-d Debugging level – for example -d and -d9
Report
-oN <filename> Normal output
-oX <filename> XML output
-oG <filename> grep-able output
-oA <basename> Output in all major formats