Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Nmap Command in Linux with Examples

  • Difficulty Level : Easy
  • Last Updated : 21 May, 2021

Nmap is Linux command-line tool for network exploration and security auditing. This tool is generally used by hackers and cybersecurity enthusiasts and even by network and system administrators. It is used for the following purposes: 

  • Real time information of a network
  • Detailed information of all the IPs activated on your network
  • Number of ports open in a network
  • Provide the list of live hosts
  • Port, OS and Host scanning

Installing Nmap Command

In case of Debian/Ubuntu 

sudo apt-get install nmap

In case of CentOS/RedHat  

yum install nmap

Working with Nmap Command

1. To scan a System with Hostname and IP address. First, Scan using Hostname 

nmap www.geeksforgeeks.org

scan-with-hostname-nmap



Now let’s Scan using IP Address 

nmap 172.217.27.174

scan-with-ip-nmap.png

The nmap command allows scanning a system in various ways. In this we are performing a scan using the hostname as “geeksforgeeks” and IP address “172.217.27.174”, to find all open ports, services, and MAC addresses on the system. 

2. To scan using “-v” option. 

nmap -v www.geeksforgeeks.org

nmap-v-option

It is used to get more detailed information about the remote machines. 

3. To scan multiple hosts  

nmap 103.76.228.244 157.240.198.35 172.217.27.174

to-scan-multiple-host



We can scan multiple hosts by writing IP addresses or hostnames with nmap. 

4. To scan whole subnet  

nmap 103.76.228.*

We can scan a whole subnet or IP range with nmap by providing “*” with it. It will scan a whole subnet and give the information about those hosts which are Up in the Network. 

5. To scan to detect firewall settings.  

sudo nmap -sA 103.76.228.244

nmap-firewall-settings

Detecting firewall settings can be useful during penetration testing and vulnerability scans. To detect it we use “-sA” option. This will provide you with information about firewall being active on the host. It uses an ACK scan to receive the information. 

6. To identify Hostnames  

sudo nmap -sL  103.76.228.244 

to-identify-hostnames-nmap

We use “sL” option to find hostnames for the given host by completing a DNS query for each one. In addition to this “-n” command can be used to skip DNS resolution, while the “-R” command can be used to always resolve DNS. 

7. To scan from a file 



nmap -iL input.txt

scan-from-file-nmap

If we have a long list of addresses that we need to scan, we can directly import a file through the command line. It will produce a scan for the given IP addresses. 
8. To get some help 

nmap -h

nmap-help1nmap-help2

We use the “-h” option if we have any questions about nmap or any of the given commands. It shows the help section for nmap command, including giving information regarding the available flags.

9. Here -A Indicates Aggressive it will let Us Know The Extra Information’s like OS Detection (-O), version detection, script scanning (-sC), and traceroute (–traceroute) even it provides a lot of valuable information About The Host.

nmap -A <Domain Name>

nmap -A

10. Using This Command we can even Discover our Target Hosting Service or Identify Additional Targets According to our Needs For Quickly Tracing the Path.

nmap --trace out <Domain Name>

nmap --trace out

11.  Here It Will Display The Operating System Where The Domain or Ip Address is Running But Will Not Display Exact Operating System Available On Computer. It Will Only Display The Chance of Operating System Available in The Computer. This Will Just Guess the Running Operating System (OS) in the Host.

nmap -O <Domain Name>

My Personal Notes arrow_drop_up
Recommended Articles
Page :