When you run this page, an Expect script "ping"s our various servers to check whether or not they're operational and displays a summary report. Since our servers are located in various network operation centres, there's a short delay while we test - and we test in parallel using expect's processes so that we don't have a very long wait if multiple machines time out.

When this page is run on our internal or training networks, it also reports on our own and delegate systems allowing us to establish quickly which systems are running on our own network.

You can learn about Expect - which sits on top of the Tcl language - on our Tcl course.

We also publish the source code of the Expect program should you wish to adopt it for your own use.