Introduction

Nmap (“Network Mapper”) is a free and open source utility for network discovery and security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running. It was designed to rapidly scan large networks, but works fine against single hosts.

Part 1 NMAP series

In this part of the series I will explain the basics of NMAP usage.

Scanning a target

When scanning an individual computer, you can use following command:

nmap <ip address of target you want to scan>

Scanning multiple targets

If you want to scan multiple targets you use the following command:

nmap <ip address 1, ip address 2, ip address 3>

Scanning a list of targets

If you want to scan multiple targets from a list, use the following commmand:

nmap -iL <targets.txt>

Scan a Range of Hosts

If you want to scan multiple targets within an IP range, use the following command:

nmap <range of IP addresses>

example: nmap 192.168.6.100-200

Scan an Entire Subnet

If you want to scan an entire subnet use the following command:

nmap [ip address/cdir]

example : nmap 192.168.6.0/24

Exclude Targets From a Scan

If you wan to exclude targets from a scan, use the following command:

nmap [targets] --exclude [targets]

Exclude Targets Using a List

If you wan to exclude targets from a scan from a list, use the following command:

nmap [targets] --excludefile [list.txt]

Wrap up part 1

This article covers the very basics of performing scans with NMAP. In next parts of this series we will cover more advanced scanning techniques.