From Plum Amazing:
Global Network Device/Application Monitoring NetCheck can identify and solve problems on your network before your users do. NetCheck is an OSX native application that provides an array of network monitoring, email alerts, logging, and reporting features. NetCheck not only provides immediate customized alerts, but also provides the historical outage information that we need to work with our business partners on quality service issues using historical patterns seen in our NetCheck logging and reporting. This enables the network administrator to identify problems and work issues that otherwise would go unnoticed. The main focus of this application is uptime monitoring of critical devices and applications, along with the features which provide this -- email alerts, logging, and reporting. You can create an EMAIL group for each special interest group and site, then create an ICMP/Port Monitoring entry that associate all devices and applications being monitored with that email group created for the site. This application was written natively in Objective C to be a native OSX application. You can install NetCheck and have it monitoring your network in a couple hours. NetCheck is a simple, efficient, and fully functional solution which provides the user with granular control of monitoring devices and applications. NetCheck is already heavily in use on a global scale.