Statsignal - Statsignal is a simple and cost-effective way to monitor your website or server and publish a status page of your system.
iperf - A TCP, UDP, and SCTP network bandwidth measurement tool
OnlineOrNot - Uptime monitoring for software teams (even teams of one).
JPerf - This project gives a better UI and new functionalities to the initial JPerf 1.
Site monitoring - Free open-source website monitoring software, easy to set up and use for monitoring web sites.
TamoSoft Throughput Test - TamoSoft Throughput Test is a utility for testing the performance of a wireless or wired network.