So I’ve used pingdom for years to monitor servers/services related to my hosting business www.serve-you.net. They offer a great service at a reasonable price, so I don’t have to setup my own monitoring hosts. They have tons of monitoring servers around the globe, which is a good way to not only monitor the up/down status, but also latency/page load times, etc.
The problem I often have though, is that monitoring servers are added/removed fairly often. I usually have pretty strict firewall rules on my servers, so allowing these servers is a must, since the activities that they perform is often seen as an attack. Pingdom publishes a list of active servers in the control panel, but keeping up with this and manually updating my firewall rules (I use CSF on my cPanel servers) can be a pain. Luckily Pingdom also has an RSS feed with the server list, though it’s in XML format of course. So I finally got around to setting up a script to automate updating the firewall rules daily with this list.