Nmap Commands

Question 1

nmap -sS scan syn

Answer 1

This is a fast technique (also referred to as half-open scanning) as the scanning host requests a connection without acknowledging it. The target’s response to the scan’s SYN packet identifies the port state.

Question 2

nmap -sT scan tcp

Answer 2

A half-open scan requires Nmap to have privileged access to the network driver so that it can craft packets. If privileged access is not available, Nmap must use the OS to attempt a full TCP connection. This type of scan is less stealthy.

Question 3

nmap -sU scan udp

Answer 3

Scan UDP ports. As these do not use ACKs, Nmap needs to wait for a response or timeout to determine the port state, so UDP scanning can take a long time. A UDP scan can be combined with a TCP scan.

Question 4

nmap -p port range

Answer 4

Use the -p argument to specify a port range.

Question 5

nmap –top-ports

Answer 5

scans top ports

Question 6

nmap -sV

Answer 6

probes for more information, such as software version.