How to Find a List of All Used IP Addresses on a Network

Identifying all of the used IP addresses on a network is useful when performing maintenance or administration changes. This is also very useful for detecting when a new device is attached to the network. Many companies perform a nightly scan of the network to check which IP addresses are in use and perform a comparison with a previous scan to identify potential security threats. Nmap is an open source scanner used by professionals and hobbyists to perform various network scanning activities. It is perfect for this activity.

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Scan the network to find all used IP addresses.

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Download the "latest stable self-installer" version of Nmap for your computer (see Resources).

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Install Nmap on your machine by double-clicking on the Nmap setup file. Follow the instructions to install it on your local drive in the default directory.

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Click the "Start" button on the Windows menu bar, type "cmd" in the text box and press "Enter" to open a command window.

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Type the following command: nmap -sP 192.168.1.0/24. Press "Enter".

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Nmap will scan the entire range of IP addresses, starting with 192.168. A list of all IP addresses in use will show with the text "host is up" below the IP address.