Scan type

1. TCP Connect Scan

nmap> nmap -sT [IP]

2. SYN Scan or Half-open Scan

nmap> nmap -sS [IP]

3. TCP ACK Scan

4. Stealth Scan

nmap> nmap -sF -p [Port] [IP]
nmap> nmap -sN -p [Port] [IP]
nmap> nmap -sX -p [Port] [IP]

5. UDP Scan

nmap> nmap -sU [IP]