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.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
tcpdump - tcpdump is a common packet analyzer that runs under the command line.
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.
tcpflow - tcpflow, a TCP Flow Recorder, is a program that captures data transmitted as part of TCP...
Ethereal - Ethereal® is used by network professionals around the world for troubleshooting, analysis...