The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
Server Check is a network utility that will help system and administrators quickly and conveniently check the availability of ports, and services on several servers at a time. The application allows you to add servers, and assign ports to ping for availability. For example, if you have a web server running apache and SSH, you can set the application to scan on ports 80, 443 and 22. You are able to edit the default ports to scan for and add your own as a global setting, or add custom ports to just specific servers.