This object specifies the URL used to check this server's availability on a specific port, by connecting to that port and attempting to retrieve a web page. This is the per-port version of the host-level URL check, letting an admin verify a specific service on a specific port of a specific server rather than relying on a single generic check for the whole host. A server running two independent web applications on different ports might have distinct values here pointing to each application's own health-check page, so a failure in one application doesn't get masked by the other's health.