If it's a web server you want to check then why not just use file() or file_get_contents() to try to retrieve something you know to be there?

(This may be bad practise, I dunno)

If I can't get a ping solution working I might have to install some webserver on the two systems in question and use the method you suggest. They're both running ubuntu and one is a VM, so to be honest that one probably doesn't really need to be checked.