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Nmap
Nmap has long been revered as a robust network security and cybersecurity tool used by engineers and SecOps professionals. It is a cross-platform utility that sports a wide range of features, including many outside simple network scanning.
It provides network scanning utilities for network exploration and offers many security auditing utilities. It provides deep forensic observation of IP packets that includes information about services, applications, OS identification, and other characteristics of the remote host. It provides "interesting ports" options to help quickly find commonly exposed ports on remote hosts.
Download the Free Nmap Security Scanner for Linux/Mac/Windows here.
Advanced IP Scanner
Most remember or have used the Advanced IP Scanner at some point. It has provided a quick way for IT and network administrators to scan their networks for years. Advanced IP Scanner is a free utility that is quick to download and very lightweight. You can start scanning your network within a couple of minutes.
It is a Windows-only tool that provides many basic scanning features, including pulling the names of devices, IP addresses, and MAC addresses with OUI lookups for vendor detection. You can export the results to a CSV file to further use the devices in other tools and documentation. You can also interact with the Wake-On-LAN functionality of remotely discovered hosts. It also provides a quick way to communicate with RDP-enabled devices.
Advanced IP Scanner offers a standalone executable that allows simply executing the program without requiring installation, making it even quicker and easier to use.
Download Advanced IP Scanner here.
Angry IP Scanner
Another popular tool in this category is Angry IP Scanner. It also works cross-platform, as it supports Windows, Mac, and Linux. Angry IP Scanner scans network ports and IP addresses.
It pings the addresses and resolves hostnames from DNS. It determines the MAC addresses of the devices for OUI lookup and can be easily extended with open-source plugins based on Java. It has many other features, such as pulling the NetBIOS name, workgroup, logged-on Windows users, web server detection, and other features. You can export scan results to CSV, TXT, XML, or IP port list files.
Angry IP Scanner offers a standalone executable that provides a quick way to get up and running with the program. However, it requires Java to be installed on the host, which can be a barrier to usage.
Download Angry IP Scanner here.
Free IP scanner by Eusing
Free IP scanner by Eusing is a simple IP scan utility with many great features. It is a fast scanner that uses multithreading technology to ensure performance. However, you can configure the priority levels of the scan process and the maximum number of threads. The vendor claims that it can scan hundreds of computers per second.
It uses ping to find hosts that are alive. It can optionally resolve hostnames, find open ports, and other features when alive hosts are found. Like other scanners, it can pull the NetBIOS information, including the hostname, workgroup, logged-on user, and MAC address. You can save the scan results to a simple text file. Unfortunately, it does not offer a standalone executable for running the program. So you will need to install it. It will ask for a registration code. However, it is a freeware program that you can use without registration.
Download Free IP scanner by Eusing here.
Built-in command line and PowerShell
While it requires a bit more work than some of the free network IP scanners, you can also leverage built-in command environments, such as the command prompt and PowerShell prompt, to find hosts on the network. For example, you can use a simple command line one-liner to quickly ping and return all hosts alive in a specific subnet:
for /l %i in (1,1,255) do @ping 10.1.149.%i -w 1 -n 1|find /i "ttl="
Microsoft also provides many great free code samples of various ping utilities built in the PowerShell gallery. I tried the ping_scan module. It worked fairly well. There are many options in the gallery for performing quick and easy ping scans of the network.
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Concluding thoughts
Free network IP scanners allow admins to monitor the network and which hosts are connected. In addition, you can find host types and device manufacturers that help with network forensics capabilities. IT admins, and SecOps professionals can use these simple tools to keep an eye on the network and provide thorough, updated network documentation.
I’ve been using Angry IP scanner for years and seen it evolve over time. I really love its ability of CSV or XML export.
I’d like to know about each product: does it give an event log or notifications that report “new device appeared” or “device disappeared”. And it should track a device across IP address changes; I want a special report if “new unknown device appeared” that is different from “known device X appeared at a new IP address”. Thanks.
Thanks for this article, I have always considered Advanced IP Scanner to be a useful tool, there are many interesting features for sysadmins.