Nmap is one of the oldest and best network enumeration software. It is located on Kali Linux and can be used on any other system. It is used for security auditing of 1 or a thousand or more systems and is a great way to detect vulnerabilities.
Their website https://nmap.org/
sudo apt-get install nmap
sudo dnf install nmap
Nmap works by attempting to poke a host or many hosts on a network for open ports. The simplest version of the command is.
nmap <host ip address or dns address>
To scan for a range of Ip addresses you can do
namp <host>-<host amount> Ie nmap 192.168.1.10-100
To scan for a specific port you can do (This will scan for open http ports)
nmap -p 80 192.168.1.10
To scan a range of ports can be done with
nmap -p 1-200 192.168.1.10
You could also scan for a range such as (This will scan port 800 on all ip addresses from 10-200)
nmap -p 80 192.168.1.10-200
nmap can also be used to detect Operating systems this isin’t the most accurate but does give a good indication.
nmap -O 192.168.1.10