We've had Net Uptime Monitor installed on three servers for a year now and it has never failed to alert us when our network connectivity drops. It even gives us details about the type of problem (eg lost packets) and location of the issue (usually the ISP). Net Uptime Monitor works reliably, easily configures itself and is straightforward to use. The free version will do the job, but if you want more detailed information about any problem you can pay £4 per server. I'm always amazed at how many web sites go down without warning - especially during busy periods like Christmas or Black Friday. A tool such as this really saves time and money because it keeps your website online and accessible all day long, which means fewer customer visits from frustrated visitors. Plus, having access to an overview of problems makes them easier to fix before they become serious issues.