Top Alternatives to PRTG Network Monitor

Zabbix is enterprise open source monitoring software for networks and applications.

AppBeat is reliable website monitoring service that alerts you when there is a downtime or failure. It also measures performance and provides functional tests.

Spiceworks is a professional network for the information technology (IT) industry.

Nagios known as Nagios Core, is a free and open source computer-software application that monitors systems, networks and infrastructure.

Datadog is a monitoring service for cloud-scale applications, bringing together data from servers, databases, tools, and services to present a unified view of an entire stack.

NetSpeedMonitor is a small Network Monitoring Toolbar for your Windows Taskbar which is designed specifically for Windows.

NetCrunch is a Windows Server–based network monitoring tool that boasts high performance and impressive scalability even in a single-server deployment.

Munin is a networked resource monitoring tool that can help analyze resource trends.

Winhotspot is a free virtual WiFi router for windows.

DU Meter is a network bandwidth monitor for your computer.

Pandora FMS (Pandora Flexible Monitoring System) is software for monitoring computer networks.

CurrPorts is network monitoring software that displays the list of all currently opened TCP/IP and UDP ports on your local computer.

Observium is a low-maintenance auto-discovering network monitoring platform supporting a wide range of device types, platforms and operating systems, etc.

BitMeter OS is a free, open-source, bandwidth monitor that works on Windows, Linux and Mac OSX.

Monitis is a web performance monitoring platform.

Cacti is a network graphing solution designed to harness the power of RRDTool's data storage and graphing functionality.

LibreNMS is an auto-discovering PHP/MySQL-based network monitoring system.

NetMeter monitors network traffic through all network connections on the computer it's installed on, and displays real-time graphical and numerical downloading and uploading speeds.

The Dude network monitor automatically scans all devices within specified subnets, draw and layout a map of your networks, monitor services of your devices and alert you in case some service has problems.

Lansweeper Network Inventory is an agentless IT asset management and Network Inventory software tool for Microsoft Windows.

Microsoft Network Monitor is discontinued a packet analyzer for capturing, viewing, and analyzing network data and deciphering network protocols.

SolarWinds Network Performance Monitor is an advanced network performance monitoring software.

BitMeter is a bandwidth meter - it allows you to visually monitor your internet connection by displaying a scrolling graph that shows your upload and download.