I'm a networking noob with three computers (Mac Minis running OS X Mavericks) on a wired LAN (Cisco 5 port fast ethernet switch). IPv4 in the network panel of each computer is configured manually with static IPs.
However, I want the application on the primary machine to give off some sort of "heartbeat" that I can remotely monitor. I was thinking I'd like to have a fourth machine that's wi-fi enabled to the LAN, have it communicate with the primary machine of the other three, and report the heartbeat to a remote server over wi-fi.
Is there a way to provide wireless Internet access (from, say, a public wi-fi) to an individual computer on the wired LAN, without 1) extending it to others, and without 2) providing a path whereby someone who wirelessly hacks into the single machine with wi-fi could gain access to the other machines on the wired LAN?