NMAP tutorial with real time examples

The following NMAP tutorials are a sample from the Ebook –NMAP Tutorials for Network Administrators

How to test the status of a FTP Server

This tutorial demonstrates how to test the status of a FTP server with nmap. FTP servers work on TCP port 21. Nmap is used to perform a TCP scan on the port 21 on the IP address of the FTP server , which is 192.168.137.2. The scan and the appropriate output are shown below (The output is shown the ebook NMAP Tutorials for Network Administrators).

It can be observed that the port is in open state, which provides the status of the server.

nmap -sS -p 21 192.168.137.2 (SCAN)

How to test the status of a DHCP Server

This tutorial demonstrates how to test the status of a DHCP server with nmap. DHCP servers work on udp port 67. Nmap is used to perform a UDP scan on the port 67 on the IP address of the Web server , which is 192.168.137.2. The scan and the appropriate output are shown below ((The output is shown the ebook NMAP Tutorials for Network Administrators)

It can be observed that the port is in open state. It can be observed that DHCP service is not running on the system, since the port is closed.

nmap -sU -p 67 192.168.137.2 (SCAN)

How to find ports open on your internet router

The tutorial explains how to find the ports open on an internet router. It is very important to find ports which are open on your internet router and disable unwanted ports, or it would increase the risk of an attacker to perform reconnaissance activities to gain illegal access to the router. The first step is to find the public IP address of the router. This can be viewed by logging into the router and checking the status tab for the internet adapter. Once the IP address is found out, setup nmap on a laptop/ system and connect to the internet using a different internet connection (Like wireless USB). Use nmap to scan the public IP address of the internet router for identifying open ports.The following nmap command would perform an intense scan on the routers public IP address and would display the open ports.

nmap -T4 -A -v IPADDRESS (SCAN)

NMAP Tutorials for Network Administrators Ebook – Click Here