How can I check if a particular IP is a server?

I figured out how to generate a list of all the IP addresses on my local network, and what I want to do is check each one to see if it is running my game as a server, perhaps through some sort of ping function. Is there any function Unity can perform to do this? My goal is to create a multiplayer LAN game where instead of requiring internet access to reach the Master Server players can start their own servers and connect with each other through the LAN, in a similar manner to games like Halo. This seems like it should be a pretty basic function but I've trawled the web and searched through UnityAnswers and come up with no leads.