The best IP Scanner alternative to NetAlertX is Nmap, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to NetAlertX and six of them are IP Scanners so hopefully you can find a suitable replacement. Other interesting IP Scanner alternatives to NetAlertX are Angry IP Scanner, Fing, NETworkManager by BornToBeRoot and Network Discovery.
NetAlertX alternatives are mainly IP Scanners, but if you're looking for
Network Analyzers or Network Monitors you can filter on that. These are just examples - use the filter bar below to find more specific alternatives to NetAlertX.