Is it possible to get the CPU status, the disk space, the memory usage of a host by just using their IP addresses? Is there a certain function in PHP that can do that?
An IP address will tell you nothing about the host on that IP address, especially since there can be multiple hosts behind that same IP.
If the host is connecting to your server via HTTP, you can check the HTTP headers to glean some information about the host, e.g. User Agent, OS, etc., but this will generally not include CPU status, disk space, or memory.