Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Dynatrace - Cloud-based quality testing, performance monitoring and analytics for mobile apps and websites. Get started with Keynote today!
Cacti - Cacti is a complete network graphing solution. It provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features.
SolarWinds NPM - Advanced network monitoring for on-premises, hybrid, and cloud. Download a FREE 30-day trial of SolarWinds Network Performance Monitor (NPM) today!