[Bash] 10 useful Nmap commands for GNU/Linux system administrators

Nmap(Network-mapper) is an open source tool that is pretty useful for networking scanning. This tool provides various options that are useful for carrying out security audits. Nmap is a powerful tool used to check the network inventory, host uptime etc. If you are a GNU/LINUX administrator, you may find the following 10 Nmap commands extremely useful

Some of the useful Nmap commands are as mentioned below:

1. Scan a single host in the network.
   

    nmap [IP-address of the host] 

2. Scan multiple hosts in the network.
   

    nmap [Hostname of the host] 

3. Scan whether a host is firewall protected
   

    nmap -sA [IP-address of the host] 

4. Scan whether a network is firewall protected
   

    nmap -sA [IP-address series of the network] 

5. Scan a full network and find out which devices are up and running
   

    nmap -sP [IP-address series of the network] 

6. Fast scan options
   

    nmap -F [IP-address series of the network] 

7. Display all open ports and also display the number of closed ports
   

    nmap --open [IP-address of the host] 

8. Scan specific ports
   

    nmap -p [port-number] [IP-address of the host] 

9. Scan the operating system of remote host
   

    nmap -O [IP-address of host] 

10. Scan the service version number of remote host
    

     nmap -sV [IP-address of the host]