Scanning used ip addresses in your network

To do this, a tool named nmap can be used. This tool can easily be installed using below command:

Ubuntu

$ sudo apt install nmap -y

CentOS/RHEL/Fedora

$ sudo yum install nmap -y

Once installed, to scan your network for used IP addresses, just run below command. Please change the network address to suit your envinronment.

$ nmap -sn 192.168.0.0/24 

You will be getting output like below, and in this case you know that 5 IPs in your network has been used.

Getting netbios name in linux

If you are using linux and administering a network full of windows machine, there is a tool called nbtscan to easily scan through the network and list all machines with their netbios name.

To install nbtscan in fedora:

# yum install nbtscan

To use it on single machine(let's say the machine's ip is 10.0.0.100):

# nbtscan 10.0.0.100

To scan the whole class C and list netbios names:

# nbtscan 10.0.0.0/24

To scan ip range:

# nbtscan 10.0.0.10-100

To get all options to use nbtscan:

# nbtscan -h