You may use Webmin's monitoring facility to periodically check the state of a remote server that does not run Webmin itself. Since we only have limited access to a remote server, we can only test its externally visible state. Nevertheless, this is a very useful tool, which can tell us whether any other server is up and running a network service on a specific port. If a service on the remote server goes down, Webmin will notify us by an e-mail.
This is an extension of the recipe, Receiving e-mail when a service stops running. Make sure you follow the setup steps in that recipe before you start this one.
In this recipe, we'll tell Webmin to periodically check if a remote web server is running and returning an expected HTML page.