How to Identify Unused IPs and Configure Static & DHCP IPs on Ubuntu Server

 

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In this blog, I'll walk you through finding unused IP addresses using Advanced IP Scanner and configuring a static IP on an Ubuntu server. I'll also show you how to switch back to DHCP with a few simple adjustments in the network configuration file. Let's start!

Finding Unused IP Addresses with Advanced IP Scanner

Finding unused IP addresses within your network is crucial for setting up a new server or device without causing IP conflicts. I recommend using Advanced IP Scanner, a free and user-friendly tool.

1. Download and Install Advanced IP Scanner
   Head over to the Advanced IP Scanner official website and download the tool.

   

   
   

2. Scan Your Network
   Launch the software, enter the IP range of your network (e.g., 192.168.1.1 to 192.168.1.255), and start the scan. The tool will display all the devices currently connected to your network and their IPs. You can use multiple networks as well. 

   

   
   

3. Identify Unused IPs

This tool will only show you the used IP Addresses with a little details. You need to identify free IP by pinging it in cmd.

Configuring a Static IP Address on Ubuntu Server

Open the network configuration file 

 sudo nano /etc/netplan/00-installer-config.yaml

Comment the configuration for DHCP

Add static ip address using below code 

Make sure you update your IP address with 192.168.1.100/24 and gateway address as well. 

network:

  version: 2

  ethernets:

    eth0:

      dhcp4: no

      addresses: 

       - 192.168.1.100/24

      gateway4: 192.168.1.1

      nameservers:

        addresses: [8.8.8.8, 8.8.4.4]

 

Apply the changes

  

netplan apply

 

Your Ubuntu server should now be accessible via the static IP you configured.

Switching from Static IP to DHCP

Open the network configuration file, uncomment DHCP configuration lines and comment static IP lines. so you can easily switch in between whenever you need to.